City of Lacey 2018 Corrosion Control Evaluation · City of Lacey 2018 Corrosion Control Evaluation 6 1.0 PROJECT BACKGROUND The Lacey Water System was regulated as a medium-sized

City of Lacey 2018 Corrosion Control Evaluation

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Contents EXECUTIVE SUMMARY .................................................................................................................................. 5

1.0 PROJECT BACKGROUND ......................................................................................................................... 6

2.0 SYSTEM INFORMATION .......................................................................................................................... 7

2.1 Water Sources .................................................................................................................................... 7

2.2 Source and Distribution System Treatment ..................................................................................... 10

2.2.1 pH Adjustment at Source S04 ................................................................................................... 10

2.2.2 Iron and Manganese Treatment Facilities ................................................................................ 10

2.2.3 Contact Time at S10 .................................................................................................................. 10

2.2.4 System-wide Chlorination ........................................................................................................ 10

2.2.5 Waterline Flushing Program ..................................................................................................... 11

2.3 Pipeline and Plumbing Materials .................................................................................................... 11

2.3.1 Distribution Lines and Facilities ................................................................................................ 11

2.3.2 Home Plumbing ......................................................................................................................... 12

3.0 WATER QUALITY DATA .......................................................................................................................... 13

3.1 Entry Point Source Water Quality .................................................................................................... 13

3.2 Distribution Tap Water Quality ........................................................................................................ 16

3.3 Residential Tap Sampling for Lead and Copper ............................................................................... 18

3.4 Customer Complaints ....................................................................................................................... 21

4.0 EVALUATION OF CURRENT CORROSION CONTROL IN THE LACEY SYSTEM ......................................... 22

4.1 Passivating Scales ............................................................................................................................. 22

4.2 Solubility Modeling .......................................................................................................................... 23

5.0 RECOMMENDED TREATMENT FOR OPTIMIZING CORROSION CONTROL ............................................ 26

5.1 Optimal Level for pH ........................................................................................................................ 26

5.2 Treatment Strategy ........................................................................................................................... 26

5.2.1 Blending Analyses and Hydraulic Modeling .................................................................................. 27

5.2.1.1 Blending Zone for Source S06 ............................................................................................... 27

5.2.1.2 Sources S24/S25 “Hot Spot” Analysis for 188 Pressure Zone .............................................. 30

5.2.1.3 Blending Zone for Source S20 ................................................................................................ 31

5.2.1.4 Blending Zone for Source S27 ................................................................................................ 32

5.3 Available pH Treatment Methods .................................................................................................... 33

5.3.1 Source S04 ................................................................................................................................. 34

5.3.2 Sources S17, S01/S18, and S23/S28 .......................................................................................... 34

6.0 ACTION PLAN ....................................................................................................................................... 35


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6.1 Schedule for Treatment Installation ................................................................................................ 35

6.2 Monitoring ........................................................................................................................................ 36

6.2.1 Distribution Monitoring ............................................................................................................ 36

6.2.2 Customer Tap Sampling ............................................................................................................ 36

6.2.3 Entry Point Monitoring.............................................................................................................. 37

6.3 Evaluation Process for Optimization ........................................................................................... 37

6.4 Considerations for Revisions to the LCR .......................................................................................... 39

6.4.1 Approach and Recommendations for Revisions Relating to New Copper Surfaces ................. 39

References .................................................................................................................................................. 40

List of Tables Table 1. Wells Supplying the Lacey Water Department .............................................................................. 7 Table 2. Average Source Water Quality Results, 2011 and 2017-2018 ..................................................... 14 Table 3. Percent annual source production during distribution sampling May 2017 – April 2018 ........... 15 Table 4. Lead and Copper at Entry To Distribution .................................................................................... 16 Table 5. Distribution Taps: Ranges of Results from Samples Collected 2017-2018 .................................. 18 Table 6. 90th percentiles for Tap Samples Collected 2016-2017 ................................................................ 20 Table 7. Summary of LCR samples collected within the 188 pressure zone .............................................. 30 Table 8. Water quality in 188 PZ when 2011 LCR samples collected ......................................................... 31 Table 9. Schedule for Installing OCCT ........................................................................................................ 35

List of Figures Figure 1. Lacey Water System Schematic .................................................................................................... 8 Figure 2. Monthly source production during distribution sampling May 2017 – April 2018 .................... 15 Figure 3. pH Ranges at Distribution Tap Sites Sampled 2017-2018 ........................................................... 17 Figure 4. Customer Tap Sample Sites, 2016-2017 ..................................................................................... 19 Figure 5. Gallons pumped from sources in 2016- 2017 during Standard LCR tap sampling .................... 20 Figure 6. Theoretical Lead (cerussite) and Copper (malachite and cupric hydroxide) Solubility at Each Entry Point .................................................................................................................................................. 23 Figure 7a, 7b and 7c. Modeled Solubilities for Lead, Aged Copper and New Copper for source group ... 25 Figure 8. Expected pH at different blending levels near Source 6 (Judd Hill) ............................................ 28 Figures 9a and 9b. Maps of Hydraulic Modeling Under Summer Operation (9a left: Blending under Current Conditions; 9b right: Predicted areas above, and below pH 7 after Treatment Installation) ....... 29 Figure 10. Expected pH at different blending levels for McAllister (S20) and treated Madrona (S23/28) 32 Figure 11. Predicted pH with source treatment at S17, S01/S18, S23/S28 ............................................... 33 Figure 12. Flowchart for Evaluating Tap Monitoring Results ..................................................................... 38

Appendices A. 2017 Letter from DOH outlining CCT steps for Lacey B. Technical Memorandum from Confluence Engineering Group, LLC (2018): pH Treatment

Recommendations C. Source Entry Point Water Quality Data D. Distribution Tap Water Quality Data


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EXECUTIVE SUMMARY In 2018, the City of Lacey Water System, PWSID # 43500Y, completed a desktop corrosion control

evaluation of the water system that meets requirements for a large system that supplies a population

>50,000. The study was triggered following 2016-2017 sampling at residential taps, and while the lead

results were very low, they were not low enough to exempt the system from completing a corrosion

control study. Consequently, the Washington State Department of Health required that the system

conduct a corrosion control study and recommend treatment for optimizing the water system for corrosion

control.

In recent years the Lacey water system has experienced a number of changes affecting water sources,

water conveyance and water treatment. This corrosion control study therefore represents water quality of

current sources supplying the system, as indicated by distribution tap samples collected for this study in

2017-2018.

Solubility modeling was used to evaluate source and distribution tap data, and indicated that the water

system is nearly optimized for lead control. The system will be optimized for lead control by ensuring pH

≥7.0 within the distribution system. While action levels for copper are met which would suggest that the

system is optimized for copper control, copper release can be lowered further by increasing pH within the

system. Although raising pH is especially beneficial to control copper release from new copper surfaces,

cross-linked polyethylene has been the material of choice by builders for the last 10-15 years. Therefore,

corrosion control treatment will be optimized when pH in the water system is raised to pH ≥ 7.0.

To achieve this water treatment goal, Lacey is proposing to install three new pH adjustment treatment

facilities, at sources S17, S01/S18, and S23/S28 to increase entry point pH at these sources to pH 7.4.

All three are wellfield locations. Treatment will be installed in a stepwise manner, to coincide with

planned replacement wells to be constructed at sources S17 and S01. In addition, dosing of caustic soda

at the existing pH adjustment facility at source S04 was increased, to increase pH at the entry from pH 7.4

to 7.6. Sources that were not selected for treatment are small sources that blend in the distribution system

with non-corrosive or treated sources, or, in the case of Sources S24 and S25, are isolated within a

pressure zone that has met Action Levels since tap sampling began in 1995. Pre-design, design and

construction of the three new facilities will occur from 2019 – 2024.

Baseline monitoring in the distribution system will track pH in the distribution as the new treatment

facilities come on-online, with particular focus on monitoring within zones that blend with untreated

sources. In 2025, after the third treatment facility is constructed and is meeting stable entry point pH

levels, customer tap samples will be collected and distribution monitoring frequency will be increased.

Because the Lacey water system is complex and has multiple blending zones, a flow chart was developed

to help evaluate tap sampling results and to identify appropriate next steps based on the monitoring

results.

The Action Plan for implementing optimal corrosion control treatment is based on meeting the

requirements of the current Lead and Copper Rule, but the City recognizes that the Federal Lead and

Copper Rule is under revision and the extent of revisions is unknown at this time. Portions of the Action

Plan may need to be revisited when the Lead and Copper Rule is revised.


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1.0 PROJECT BACKGROUND The Lacey Water System was regulated as a medium-sized system under the Federal Lead and Copper

Rule until 2010, when notified by the Washington State Department of Health (DOH) that the system

must complete the corrosion control requirements for a system serving >50,000 people. In December

2010, Lacey notified DOH of its intent to conduct a corrosion control study and complete subsequent

corrosion control treatment steps. At the time, Lacey was planning to construct a pH adjustment facility

for source S04 in 2011, and was anticipating that water purchased from the City of Olympia was going to

change from surface water to a groundwater source.

The final study report1 was completed and submitted to DOH in March 2014. The report included

distribution data collected after the source S04 pH adjustment facility became operational, and concluded

that the Lacey water system would be fully optimized when water from source S30 (intertie with the City

of Olympia) was treated to increase its pH, and when source S01 (an infrequently-used source) was

replaced. DOH approved the conclusions in the report in April 2014. However, by 2015 Lacey started

planning for inactivating the Olympia intertie as a permanent source, and met with DOH in early 2016 to

discuss remaining corrosion control steps. The parties agreed that Lacey could collect lead and copper

tap samples after the intertie was inactivated, to evaluate whether the Lacey system would now qualify for

the (b)(3) exemption2. Meeting the exemption would eliminate the need for completing the corrosion

control study. Tap samples were collected in 2016-2017, and whereas the results for lead were very low,

they did not meet the criteria for a (b)(3) exemption.

In February 2017 DOH provided notice to Lacey to complete a corrosion control study by August 2018.

The letter from DOH is attached as Appendix A. The expectation is for Lacey to collect additional

distribution and source samples to represent the current sources of supply to the system, to update the

analyses and recommend additional treatment to optimize the system for corrosion control.

Lacey contracted Confluence Engineering Group (“Confluence”) to analyze the updated data, make

treatment recommendations, and identify treatment goals for Lacey sources. These analyses and

recommendations are summarized in this updated report, and are based on a Technical Memorandum

from Confluence that is attached to this report (Appendix B).

1 City of Lacey Corrosion Control Evaluation Final Report March 2014 2 40 CFR 141.81(b)(3) states a water system is deemed to be optimized for corrosion control if results from two consecutive 6-month monitoring periods demonstrate that the difference between the 90th percentile tap water lead level and the highest source water lead concentration is < 0.005 mg/L.


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2.0 SYSTEM INFORMATION

The Lacey water system includes three treatment facilities (see Section 2.2), seven storage reservoirs, and

seven primary pressure zones and three sub-zones that serve clients at varying elevations. A schematic

showing the distribution system, major facilities and pressure zones is shown in Figure 1.

2.1 Water Sources The Lacey water system is completely self-supplied with 20 groundwater wells that are owned and

operated by the city (Table 1). Source S01, though, has been offline since 2016 and is planned to be

replaced in 2020. As shown on the Water Facilities Inventory (WFI), the system has 16 regulated sources

that include 12 individual wells and 4 wellfields (with two wells per wellfield). Sources that are regulated

as wellfields are noted in Table 1. All sources are approved for year-round supply.

Table 1. Wells Supplying the Lacey Water Department

DOH ID Source Name(s) Year Online Completed Depth (ft)

Aquifer

S01 Well 1 1965 122 Qga

S021 Well 2 1969 217 Qpg

S031 Well 3 1969 225 Qpg

S04 Well 4 1973 84 Qga

S06 Well 6C; Judd Hill 1993 385 Qpg/TQu

S07 Well 7 1976 479 TQu

S09 Well 9 1981 290 TQu

S10 Well 10 1981 212 Qpg

S152 Beachcrest well 1 1976 140 Qga

S162 Beachcrest well 2 1979 138 Qga

S193 Hawks Prairie Well 1 1994 646 TQu

S20 McAllister 1995 214 Qpg

S214 Madrona well 1 1997 329 Qpg


S24 Nisqually Well 19A 1986 107 Qpg

S25 Nisqually Well 19C 1972 79 Qpg

S27 Evergreen Estates 2003 282 Qpg


S29 Betti well 2005 390 Qpg

S313 Hawks Prairie Well 2 2013 656 TQu 1 Regulated as wellfield S18 by DOH 2 Regulated as wellfield S17 by DOH 3 Regulated as wellfield S32 by DOH 4 Regulated as wellfield S23 by DOH


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Figure 1. Lacey Water System Schematic


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2.2 Source and Distribution System Treatment

Source treatment in the Lacey water system consists of three treatment facilities: a pH adjustment

facility, and two iron and manganese treatment facilities. In addition, a contact time chamber was

constructed at source S10. Water quality in the distribution system is maintained with system-wide

chlorination and a routine waterline flushing program. Treatment facilities and water quality programs

are described below.

2.2.1 pH Adjustment at Source S04 Although treatment was not triggered by source or tap sample results, Lacey’s comprehensive water

system plans recommended corrosion control at source S04 to address a history of corrosion of new

copper pipe in the vicinity of the well. The facility was constructed in 2012-2013.

The facility was designed to treat source water with 25% caustic soda (sodium hydroxide solution) to

achieve a target pH of 7.6 and alkalinity within 40-70 mg/L. Evaluations of water quality and treatment

alternatives for source S04 concluded that low pH was the primary factor affecting the corrosivity of the

water, and results from a relatively high concentration of dissolved carbon dioxide compared to nearby

sources S09 and S10 (HDR 2007). pH adjustment was determined to be more suitable for corrosion

control than calcium carbonate precipitation and corrosion inhibitor chemicals because well 4 supplies a

pressure zone that is fed by multiple wells, and will blend with other sources in the system that do not

need corrosion control treatment (HDR 2007). pH adjustment using caustic soda was the recommended

treatment for source S04 based on its ability to meet treatment goals along with its process flexibility,

lower capital cost and footprint, and simplicity of operation (HDR, 2007).

2.2.2 Iron and Manganese Treatment Facilities The city operates two iron and manganese treatment facilities. The first was a design-build ATEC facility

constructed at source S07 in 2001. The well 7 ATEC facility oxidizes iron and manganese with

potassium permanganate and 0.8% sodium hypochlorite prior to filtering through pyrolusite media. The

second facility, referred to as the Hawks Prairie Water Treatment Facility (HPWTF), was constructed at

source S19 in 2008 with capacity to also treat future source S31. The HPWTF oxidizes constituents in

raw S19/S31 water with air injection followed by 0.8% sodium hypochlorite injection. Then the water

containing the oxidants is filtered through manganese greensand before passing through a contact time

chamber to achieve breakpoint chlorination.

Both iron and manganese treatment facilities were designed to meet target finished water goals of <0.15

mg/L for iron, and <0.025 mg/L for manganese (<50% of the MCLs for iron and manganese).

2.2.3 Contact Time at S10 A contact time chamber at well 10 (S10) was installed in 2007, after numerous coliform-positive samples

occurred following a well rehabilitation project. The same 0.8% sodium hypochlorite solution used for

system disinfection is injected into raw water, which then passes through an underground contact time

chamber. Raw source water is sampled quarterly for bacteria, but coliforms have not been detected since

the contact time chamber was constructed. Since primary source disinfection is not required at this time,

contact time is provided but Lacey does not list this as a disinfected source.

2.2.4 System-wide Chlorination The Lacey water system has been chlorinated on a permanent basis since 2005. System-wide chlorination

was initiated after several non-acute total coliform violations occurred in 2004 – 2005. The violations


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were not attributed to source wells so 0.8% sodium hypochlorite is injected at all well sites for the

purpose of maintaining a disinfectant residual in the distribution system. Chlorination is intended to

achieve a target concentration of approximately 0.5 mg/L free chlorine in the distribution system,

although typically concentrations range from 0.4 – 0.8 mg/L.

2.2.5 Waterline Flushing Program The city started a routine unidirectional flushing (UDF) program in 2004. UDF systematically progresses

from source(s) to the periphery of the distribution system, and uses water valves to isolate and control

flow direction and velocities that scour the waterlines. The progression from source to periphery ensures

that “clean” water is used for flushing each section of pipe and that material cleaned from pipe walls is

discharged from the system to an appropriate discharge location.

Lacey’s UDF program was initiated to address frequent and extreme brown water events that could not be

controlled by spot flushing, and to prepare the distribution system for system-wide chlorination. The

initial two years of the program focused on removing legacy iron and manganese deposits, as well as

reducing biofilms containing iron and sulfur bacteria. The UDF program is now focused on preventing

brown water episodes by removing residual iron and manganese deposits, to raise chlorine residuals in

dead ends, and to manage iron and sulfur bacteria that are still present but are greatly inhibited by

chlorine and water treatment that reduces available food sources. Generally, the entire system is flushed

over a 3-5 year cycle although some areas of the system are flushed every 1-2 years. Lacey may expand

the program in the future to include service line flushing and targeted waterline swabbing.

2.3 Pipeline and Plumbing Materials Pipeline and plumbing materials provide the source of metals that can be leached into drinking water.

Materials can include copper, iron and galvanized metal used in piping; brass fixtures and fittings

containing lead, arsenic and/or zinc; and fluxes and solder used in both manufacture and installation of

piping.

2.3.1 Distribution Lines and Facilities Distribution lines

At the beginning of 2018, the distribution system consisted of approximately 2.1 million linear feet of

water main. The majority of pipe is six to twelve inches in diameter.

The approximate percentages of materials in the distribution system are as follows:

PVC or Polyethylene: 59.5 %

Lined Ductile Iron: 21.8%

Asbestos Cement: 16.8%

Other (includes concrete, galvanized metal, and “unknown”): 2%

Although asbestos cement can be vulnerable to corrosion, city staffs have observed that tree roots cause

the most damage to asbestos cement waterlines. Waterlines with a history of leaks and breaks are

identified for replacement through the city’s semi-annual waterline replacement program, and often

includes replacing some asbestos cement pipe. Operations and maintenance staffs have observed

evidence of corrosion in the water system such as tuberculated parts and fittings. However, many breaks


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and leaks are attributed to poor materials, such as bad gaskets or older non-standard valves and fittings, or

poor installation. Waterline corrosion has not been cited as a reason for waterline repairs or replacement.

Lead service lines have not been used in the Lacey Water system, and lead goosenecks have not been

found in older parts of the system that were constructed with non-standard materials. The Lacey water

system itself was created in 1968, well after lead goosenecks were commonly used, and the city’s

waterline replacement program has replaced waterlines and service connections from many of the

acquired water systems.

Water System Components

All new and replaced water system components meet NSF materials requirements and AWWA standards.

However, non-standard components such as fittings and valves were used in some water systems acquired

by the City of Lacey, particularly in the Huntamer’s Water System that became the Lacey Water System

in 1968. Lacey replaces non-standard materials when they are found during repairs or as part of waterline

replacement projects.

The Reduction of Lead in Drinking Water Act took effect in January 2014 and requires all materials used

in water systems, brasses in particular, to be certified lead-free. This Act amended the Safe Drinking

Water Act to reduce the allowable lead content in all products in contact with drinking water from 8% to

a weighted average of 0.25% (using a wetted surface based averaging formula). The new lead-free

components are certified under NSF/ANSI Standard 372. The only allowable exceptions are for devices

associated with non-potable uses, such as toilets, tub fillers, shower valves, and service saddles. In

addition, fire hydrants and water main gate valves 2” or greater in diameter are exempt from meeting the

no-lead requirements. The intent of the Reduction of Lead in Drinking Water Act is to directly address

lead release into drinking water. Studies have shown that lead-free brass alloy components release

minimal amounts of lead and other metals compared to lead-containing components (Sandvig 2009).

Before January 2014, Lacey started transitioning to the new lead-free components as they became

available.

Dezincification of brass fittings has been associated with lead release into drinking water and has caused

large failures in some water systems. Zhang and Edwards (2011) reported that use of dezincification-

resistant and low zinc brasses created a higher risk for lead release compared to brasses with higher zinc

content, especially if the low-zinc product was not also low-lead or lead-free. There are no indications

that dezincification has been a problem in the Lacey water system.

2.3.2 Home Plumbing In the Lacey water service area, materials used in home plumbing are predominately copper and cross

linked polyethylene (PEX), although galvanized pipe and PVC have also been used. Copper pipe was

used extensively in new construction in the 1980s and 1990s, but over the past fifteen years the use of

PEX for water plumbing has increased steadily and is now used in the construction of most commercial

buildings and subdivisions. At the time of the 2014 Corrosion Study, Lacey’s Building Official estimated

that PEX was used in at least 80% of new construction served by the Lacey water system. By 2018, PEX

is reported as the material of choice by contractors that construct the vast majority of new housing served

by the Lacey water system, and consequently is being used in almost all new residential construction

(Wade Duffy, Lacey Building Official, pers. comm.).

The city’s materials surveys have mainly focused on identifying single-family residences that qualify as

Tier One sites for residential lead and copper tap sampling under the current Lead and Copper Rule, i.e.,

residences constructed between 1983-1986 and with all (or mostly all) original plumbing. The original


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pool of Tier One homes used for tap sampling declined as older homes were renovated, or replaced, so in

2016 county parcel information was used to identify homes served by the water system that were

constructed between 1983-1986. During this construction period approximately 1,340 homes were built,

which represents <6% of the single family connections to the water system. This list was used to contact

residences for participating in tap sampling in 2016-2017; sampling results are summarized in Section

3.3.

3.0 WATER QUALITY DATA This Section describes source (entry point) water quality and distribution system water quality from

samples collected for the 2014 Corrosion Control Study and this 2018 Corrosion Control Study Update.

Residential tap sample results for lead and copper results are also presented here.

3.1 Entry Point Source Water Quality For this updated corrosion control study, source samples were collected quarterly in 2017-2018 to

characterize water quality of sources currently supplying the Lacey water system. Changes in sources

since the 2014 study are the following:

Source S04 has been treated with caustic soda since 2013 to raise pH.

Source S30 (intertie with Olympia) was inactivated in 2016.

Source S01, identified in the 2014 study as a corrosive source, was offline during 2017-2018 due

to pumping issues and is anticipated to remain offline until it is replaced (planned for 2020). As

a result, this source was only sampled once for this study.

Source S31 was approved as a new source and was used in 2015-2016, but was offline from late

2016 through May 2018 due to sanding and mechanical issues. As a result, this source was not

sampled for this study but its construction report indicates water quality very similar to source

S19. Both sources are treated for iron and manganese at the Hawks Prairie Treatment Facility.

For this study, sources were sampled quarterly from July 2017 to April 2018. Data collection for this

study focused on parameters identified by DOH (Appendix A). Water samples were analyzed for

alkalinity, calcium, and sulfate; in addition, temperature, pH, specific conductance, and free and total

chlorine were measured in the field. Sources were also sampled quarterly in 2011 for the 2014 study. All

water quality results from 2011 and 2017-2018 are compiled in Appendix C. Average results are

summarized in Table 2.

Monthly water production from sources is summarized in Figure 2 for the period when water quality

samples were collected. Table 3 summarizes these data as percent annual production.


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Table 2. Average Source Water Quality Results, 2011 and 2017-2018

Site Temp

°C pH

Specific Conduc-

tance (µS/cm)

TDS (mg/L)

Free Chlorine (mg/L)

Total Chlorine (mg/L)

Alkalinity (mg/L

CaCO3)

Hardness (mg/L

CaCO3)

Calcium (mg/L)

Iron (mg/L)

Manganese (mg/L)

Silica (mg/L)

Chloride (mg/L)

Sulfate (mg/L)

S01 11.3 6.63 193.7 96.8 0.53 0.56 71.4 72.7 46.3 0.17 <0.01 48.5 6.2 8.3

S18 11.4 6.83 203.2 100.1 0.53 0.57 86.3 78.4 53.5 <0.1 <0.01 41.3 5.6 7.4

S04* 12.6 7.39 207.9 98.4 0.52 0.54 72.2 55.0 43.0 <0.1 <0.01 24.5 0.0 11.0

S06 11.2 6.86 191.7 94.8 0.45 0.52 76.7 78.3 46.9 <0.1 <0.01 44.0 6.2 12.1

S07 10.6 7.41 201.8 99.6 0.62 0.75 81.3 81.4 47.9 <0.1 <0.01 47.3 8.0 12.5

S09 10.8 7.63 122.7 60.3 0.66 1.10 43.3 38.1 24.3 0.07 0.05 54.3 7.4 6.0

S10 11.3 7.50 169.8 83.6 0.54 0.59 64.0 64.0 47.5 <0.1 <0.01 31.3 7.0 11.5

S17 10.6 7.00 263.3 130.8 0.67 0.73 98.0 110.8 74.8 0.03 0.01 32.3 10.4 10.1

S19 11.4 7.61 115.7 56.8 0.69 0.82 40.0 32.6 20.4 <0.1 0.01 49.0 8.7 2.3

S20 11.7 6.96 195.4 96.0 0.61 0.64 67.6 60.8 52.3 <0.1 <0.01 41.5 7.4 8.0

S23 13.6 7.00 183.5 90.4 0.42 0.46 65.6 62.4 50.4 <0.1 <0.01 38.5 6.8 7.6

S24 11.5 7.11 134.5 66.0 0.57 0.61 57.8 51.1 35.5 <0.1 <0.01 38.8 5.6 4.0

S25 11.5 6.90 140.8 69.3 0.52 0.58 60.0 53.5 35.3 <0.1 <0.01 41.8 5.8 3.4

S27 11.5 6.98 179.1 87.6 0.55 0.59 59.8 70.4 51.7 <0.1 <0.01 35.7 6.5 7.0

S28 12.9 7.01 187.5 93.0 0.44 0.49 64.9 75.0 49.8 <0.1 <0.01 38.3 7.0 7.6

S29 11.2 7.13 322.6 164.8 0.59 0.64 134.6 153.1 102.1 <0.1 <0.01 37.5 22.0 10.4

*Results for pH and alkalinity from S04 are entry point samples collected from 2013-2018 (after installation of pH adjustment)

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Figure 2. Monthly source production during distribution sampling May 2017 – April 2018

Table 3. Percent annual source production during distribution sampling May 2017 – April 2018

Well S01 S18 S04 S06 S07 S09 S10 S17 S20 S23 S24 S25 S27 S28 S29 S32

% 0 11.76 5.37 3 21.56 1.84 10.71 2.74 6.85 8.42 0.29 0.69 8.42 2.01 7.63 8.74

0

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

300,000,000

350,000,000

400,000,000

450,000,000ga

llon

s p

rod

uce

d

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Table 4 provides lead and copper from corrosion study samples and compliance inorganic contaminant

(IOC) samples collected within the study periods. Lead and copper concentrations are below detection

limits at most entry points, although there have been intermittent detections of both lead and copper.

Table 4. Lead and Copper at Entry To Distribution

Compliance IOC Data,

2008 - 2010 2011 Study

Dec 2016 source

samples

Compliance IOC Data, 2017

2017-2018 Study

Source Lead

(mg/L) Copper (mg/L)

Lead (mg/L)

Lead mg/L)

Lead (mg/L)

Copper (mg/L)

Lead (mg/L)

S01 <0.002 < 0.02 <0.001 <0.001 0.001 < 0.02 NS

S04 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S06 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S07 <0.001 0.03 <0.001 <0.001 <0.001 0.03 <0.001

S09 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S10 <0.002 < 0.02 <0.001 0.001 <0.001 < 0.02 <0.001

S17 <0.001 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S18 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S19 <0.002 < 0.02 <0.001 <0.001 NS NS <0.001

S20 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S23 0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S24 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S25 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S27 <0.002 < 0.02 <0.001 <0.001 <0.001 < 0.02 <0.001

S28 0.004 < 0.02 <0.001 <0.001 <0.001 0.05 <0.001

S29 <0.002 0.04 <0.001 <0.001 NS NS <0.001

NS = not sampled

3.2 Distribution Tap Water Quality

Twelve distribution taps (sample stations) were sampled at least quarterly from July 2017 to April 2018 to

represent water quality in the distribution when supplied by sources currently used by the City of Lacey.

Locations of the taps in relation to the system’s pressures zones are shown in Figure 3. Eight of the sites

were also sampled quarterly in 2011 for the 2014 Corrosion Control Study; sites were originally selected

from Lacey’s Stage 1 and Stage 2 disinfection byproducts sampling programs but changes were made to

improve the geographic distribution and to sample near Tier One sites where customer lead and copper

tap samples were collected in 2016-2017

The ranges of water quality parameters sampled in 2017-2018 are provided in Table 2, and the ranges of

pH at the tap sites are shown in Figure 3. The pH results, in particular, illustrate how pH in the

distribution system increased from not using S01 or the intertie with Olympia; in 2011, the minimum pH

measured in the distribution system was 6.5, but was 6.8 in 2017-2018. These results also support the

selection of sources for corrosion control, discussed further in Section 5.

17

Figure 3. pH Ranges at Distribution Tap Sites Sampled 2017-2018 Orange and red dots show blending zones for sources S06, S17, S18, S20, S27, S23/S28, S24 and S25

S27

S09 9

Source well, ID#

Distribution Sample Site Source well #

S28

S10 9

S04 9

S01

S06

S07

S20

S23

S24

S29

S25

S18 9

SS90 S07

SS30 S07

SS55 S07

SS12 S07

SS14 S07

SS11

1 S07

SS41

1 S07 SS02

1 S07 SS91

1 S07 SS17

1 S07

SS07

1 S07 SS65

1 S07

18

Results for key parameters are summarized below in Table 5, and all results are provided in Appendix D.

The ranges of results in Table 5 reflect the variations in water quality between the aquifers that supply the

Lacey system. Distribution tap sites in the south part of the 337 zone showed the most variability

between sampling rounds, reflecting the differences in water quality between sources S04, S09 and S10

that supply this area, and the high variability in the usage of these sources. Sites with high values for

conductivity, alkalinity and hardness also indicate the migration of water from source S29, which pumps

into the 400 zone but can supply the 337 zone via the Britton Parkway PRV.

Table 5. Distribution Taps: Ranges of Results from Samples Collected 2017-2018

Sample Station (pressure

zone)

pH (s.u.)

Temperature (◦C)

Specific Conductance

(µS/cm)

Alkalinity (mg/L

CaCO3)

Calcium (mg/L)

Sulfate (mg/L)

SS36 400 zone

7.3–7.7 9.0-17.3 104-159 41-57 23-32 2-4

SS20 400 zone

6.8-7.7 8.2-15.2 119-250 45-104 28-91 3-11

SS12 400 zone

7.0-7.1 8.4-15.9 172-206 61-73 45-49 7-8

SS30 400 zone

7.1-7.7 8.4-21.3 109-233 48-96 30-80 3-9

SS91 400 zone

7.0-7.4 8.4-13.9 171-250 60-83 49-60 7-13

SS55 188 zone

6.9-7.1 8.7-16.7 136-154 58-65 33-39 4

SS90 224 zone

7.1-7.5 7.9-19.1 163-280 62-119 43-108 6-13

SS07 337 zone

6.9-7.2 8.2-12.8 157-216 60-68 39-52 7-8

SS02 337 zone

7.0-7.4 8.5-21.2 188-217 76-90 40-64 13

SS17 337 zone

7.0-7.4 8.7-16.5 168-210 69-88 48-64 8-13

SS11 337 zone

6.8-7.3 9.2-15.9 188-288 84-91.2 55-71 8-13

SS14 337 zone

7.1-7.4 9.3-18.3 187-283 46-109 42-70 11-13

3.3 Residential Tap Sampling for Lead and Copper Residential tap samples were collected in September 2016 and March 2017 to evaluate whether the

inactivation of the Olympia intertie was sufficient for optimizing corrosion control in the Lacey water

system. Source samples for lead were also collected in December 2017. Locations that were sampled are

shown in Figure 4, which also shows locations where lead concentrations were above the maximum

quantifiable level of 0.005 mg/L. As shown in Table 6, the 90th percentiles for both lead and copper were

below Action Levels. However, the September 2016 results did not meet the requirements for a (b)(3)

exemption because the difference between the 90th percentile and the highest source lead concentration

(0.001 mg/L) was not < 0.005 mg/L. Sources supplying the system during customer tap sampling are

shown in Figure 5.

19

Figure 4. Customer Tap Sample Sites, 2016-2017

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Zone 337

Zone 400Zone 224

Zone 188

Zone 275

Zone 375

Zone 460

Zone 211

Zone 422

Lead and copper tap sites sampled for first time in 2016-2017

= Lead results ≥ 0.005 mg/L = Lead results < 0.005 mg/L

20

Table 6. 90th percentiles for Tap Samples Collected 2016-2017

Year Number of

tap samples

mg/L Lead mg/L Copper

90th percentile

Max result

90th percentile

Max result

1992 0.008 0.85

1995 0.003 0.70

1996 <0.002 0.50

1999 30 0.003 0.010 1.00 1.96

2002 30 0.008 0.012 0.92 1.8

2005 30 0.004 0.015 0.95 2.3

2008 31 0.008 0.010 0.96 1.4

2011 30 0.004 0.023 0.84 1.2

2014 30 0.006 0.011 0.86 1.2

2016 67 0.006 0.049 0.81 1.3

2017 63 0.005 0.019 0.69 1.1

Source of table: Confluence (2018)

The history of tap sampling for the main Lacey system is provided in Table 6; note that prior to 1998, the

Lacey system included the main system, and two satellite systems. The systems were consolidated in

1998. Over the history of tap sampling, lead concentrations have generally been low, and 90th percentiles

were below Action Levels during each sampling period. For copper, 90th percentiles have also been

below Action Levels but maximum results were higher during earlier sampling rounds.

Overall, tap sample results illustrate that the Lacey system has been in compliance with Action Levels,

and while lead concentrations are generally low, copper release is more of an issue.

Figure 5. Gallons pumped from sources in 2016- 2017 during Standard LCR tap sampling

0

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

300,000,000

350,000,000

400,000,000

450,000,000

gallo

ns

pu

mp

ed

S30

S32

S29

S28

S27

S25

S24

S23

S20

S17

S10

S09

S07

21

3.4 Customer Complaints

The city started maintaining a database of water quality and pressure complaints in 1998. As shown in

Table 6, in recent years most documented water quality complaints are regarding brown water and brown

staining, followed by taste and odor, and chlorine. The 2014 study report describes in more detail the

history of copper-related customer complaints that were received by the city from 1993-1998. Most of

the complaints were from new construction in that time period, especially in the vicinity of untreated

Lacey source S04. Since the pH adjustment facility for S04 came online in 2013, the city has received

only one complaint related to copper staining. However, as discussed in Section 2.3.2, in the last 15 years

or so, the use of copper plumbing in residences has declined considerably and is now relatively rare.

Complaints relating to hard water increased after source S29 came online in 2006. Complaints have

transitioned to questions, typically regarding what is scale and how to prevent scale buildup, and to

request data to support the selection of on-premise water softening treatment; questions and data requests

are not included in the complaint database.

Table 6. Customer Water Quality Complaints, 1998 – 2017

Year Brown water/

brown staining

Blue water/ blue staining

Taste and Odor

Chlorine taste/odor

Scale/ hard water

Pressure high/low

19941 15+

1998 21 10 4 0 0 33

1999 6 unknown2 0 0 0 14

2000 13 2 10 1 0 52

2001 20 5 9 0 1 30

2002 148 2 20 0 0 46

2003 223 4 18 0 0 47

2004 64 3 23 6 0 25

2005 15 5 8 17 1 43

2006 32 4 6 4 2 33

2007 30 0 7 7 5 39

2008 16 0 2 8 0 18

2009 9 0 4 11 2 20

2010 9 0 4 5 0 23

2011 17 0 7 10 0 14

2012 18 0 2 9 3 1

2013 14 0 11 10 1 2

2014 14 1 11 5 0 0

2015 15 0 4 9 0 0

2016 35 0 14 5 1 0

2017 23 0 8 9 0 2 1 the complaint database started in 1998; complaints related to copper in 1994 are from files 2 none recorded in the database

22

4.0 EVALUATION OF CURRENT CORROSION CONTROL IN THE LACEY SYSTEM

Lacey’s 2014 Corrosion Control Study concluded that pH adjustment at sources S04, S30 and S01 would

optimize the system by addressing the most corrosive sources and by increasing the pH profile within the

distribution system. At the time, corrosion control treatment at S04 was provided using caustic soda, and

the City of Olympia was planning to install aeration to treat their McAllister wellfield (Lacey source

S30). However, to date S04 is Lacey’s only source with corrosion control treatment, since neither S01

nor S30 are supplying the system.

For this 2018 Study update, water quality data from Section 3 were used to evaluate sources that are

currently supplying the Lacey system. Because corrosion scales play an important role in metals release,

this section includes a discussion on corrosion scales, followed by an evaluation of the solubility of lead

and copper scales as a function of pH and dissolved inorganic carbon (DIC) found at each of Lacey’s

sources. This solubility analysis forms the basis of the treatment recommendations discussed in Section

5. The analysis in this section, and treatment recommendations in Section 5, are from solubility modeling

and a water quality evaluation conducted by Confluence Engineering Group, LLC for the City.

Confluence provided their findings and recommendations in a Technical Memorandum that is

summarized below and cited within this report as Confluence (2018). The full Technical Memorandum is

provided in Appendix B.

4.1 Passivating Scales

Passivating scales are corrosion products that form and accumulate on the pipe surface, leaving protective

layers (scale) that suppress further metal release. Confluence (2018) described that, “scales can be

complex, layered, and impacted by the water quality the pipe has been exposed to in the past.” Scales can

form naturally over time, but can also be induced by pH/alkalinity adjustment or the addition of corrosion

inhibitors.

Whereas corrosion is the electrochemical interaction that mobilizes lead and copper from source

materials, interactions between corrosion products (scales) and the physical, chemical and biological

characteristics of water will affect the release of metals into drinking water. However, source water

quality is often the main driver for metals release.

Copper

On copper pipe, the initial scales that form depend on water quality and physical properties. Generally in

new pipe the initial scales that form on elemental copper are cupric hydroxide (Cu(OH)2) and cuprite

(Cu2O), which are relatively soluble scales. Total copper release is initially controlled by oxidation-

reduction reactions, and as the layers form and age, precipitation and dissolution can become the primary

mechanisms controlling copper release (Xiao et al., 2007). The chemistry of the pipe surface will change

as the scales form, dehydrate, grow thicker, and age. Generally the most corrosion protection is provided

when outer scales consist of relatively insoluble forms such as tenorite (CuO) or malachite (Cu2 (OH)2

CO3). Formation of these scales will depend on conditions present in the system that can either hasten or

inhibit the transition to these more insoluble forms. Another complicating factor is that one or more

forms of scale can be present, and can control the release of soluble as well as particulate copper (Xiao et

al., 2007).

Lead

Scales that form on lead-containing pipes and fixtures are typically dominated by hydrocerussite

(Pb(II)3(CO3)2(OH)2) or cerussite (Pb(II)CO3). Lead oxide (PbO2) can dominate under highly oxidizing

conditions, such as maintaining a high free chlorine residual. Other lead scales can dominate but co-occur

with these lead carbonate scales in the presence of high alkalinity or pH >10. When corrosion inhibitors

23

are used, lead scales formed will depend on whether orthophosphate or blended phosphates are used (EPA

2016).

4.2 Solubility Modeling The Lacey water system is complex; it has multiple pressure zones and multiple source entry points. The

twenty sources supplying the system draw from three aquifers with varying water quality characteristics.

Passivating scales that form in residential plumbing will vary depending on which sources supply the

homes, whether scale is in equilibrium with water, and whether there are other physical, chemical or

biological factors affecting corrosion. Although models cannot address all of these factors to predict

absolute values for solubility of lead and copper scales, models can provide conservative estimates of

likely trends in solubility (Confluence 2018). Solubility modeling for this study was conducted by

Confluence Engineering Group LLC using WaterPro 6.30.

The solubilities of lead and copper were modeled for each source, using median water quality values at

source entry points and the dominant scales expected to be present. Lead solubility was modeled for

cerussite as the dominant lead scale present, and modeling predicted little variability between sources for

lead solubility.

Because aging of copper scale is a significant factor for copper control, Confluence modeled copper

solubility for both insoluble cupric hydroxide scale and soluble malachite scales. The predicted

solubilities of lead and copper are shown in Figure 6. As shown in the figure, sources S04, S07, S09, S10

and S19/S32 are the least corrosive to copper scale typically formed in new copper pipe (cupric

hydroxide), and sources S06, S17 and S18 are the most corrosive to new copper pipe. However, once

scales age and malachite scale is formed, copper solubility at all sources is predicted to be reduced

considerably.

Figure 6. Theoretical Lead (cerussite) and Copper (malachite and cupric hydroxide) Solubility at Each Entry Point (source: Confluence(2018))

24

Confluence then grouped the sources based on pH and DIC (Table 7) and used solubility modeling to

evaluate the impact of pH adjustment on lead and copper solubilities. Figure 7 shows the modeled

solubilities of lead, aged copper and new copper for these groups.

Table 7. Source Grouping under Current Treatment Conditions

Group Sources DIC mg/L as C

pH s.u.

TDS mg/L

Ca mg/L

ALK mg/L as CaCO3

G1 9, 32 10-11 7.6-7.7 57-59 21-25 40-43

G2 20,23,24,25,27,28 15-21 6.9-7.0 59-97 36-55 55-67

G3 4,7,10 17-22 7.4-7.5 83-102 42-52 64-83

G4 6,17,18 24-30 6.9-7.0 93-132 47-80 76-98

G5 29 40 7.15 181 116 140

Source: Confluence (2018) Based on the solubility modeling results for individual sources and the grouped sources, Confluence

(2018) reached the following conclusions:

Lead solubility is in good control as long as pH is ≥7.0.

Given that the system is in compliance with the copper action level, the sources are optimized for

copper under the existing lead and copper rule but there can be some marginal benefit by raising pH

to ≥ 7.0 if tenorite is present on aged pipe surfaces.

The Group 1 wells (S09 and S32) and Group 3 wells (treated source S04, and sources S07 and S10)

have water quality that is not corrosive to lead or copper.

The sources with combined higher DIC and lower pH are the most corrosive to new copper surfaces.

These include the Group 4 wells (sources S06, S17 and S18) which have pH from 6.9 – 7.0 and DIC

of approximately 30 mg/L, and the Group 2 wells (sources S20, S23, S27, S28, S24 and S25) which

have pH from 6.9.-7.1 and DIC of approximately 20 mg/L.

Source S29 (Group 5) has low pH and high DIC, which not corrosive to lead but is corrosive to new

copper due to its high DIC.

Source S01 is highly corrosive based on data collected for the 2014 study, but was not included in

this analysis because it has been offline and the City plans to replace the well.

These observations and conclusions were then used to recommend a treatment strategy.

25

Figure 7a, 7b and 7c. Modeled Solubilities for Lead, Aged Copper and New Copper for source groups

26

5.0 RECOMMENDED TREATMENT FOR OPTIMIZING CORROSION CONTROL Confluence used results from solubility modeling along with source and distribution water quality to

develop optimal water quality parameters and a prioritized, step-wise treatment strategy for adjusting pH

at selected source wells. Treatment is focused on meeting requirements of the existing Lead and Copper

Rule. Considerations for meeting anticipated changes to the Lead and Copper Rule, including revised

treatment goals, are discussed in Section 6.4.

Confluence recommended treatment at selected sources with the objective of raising the pH profile within

the distribution system. This approach was selected mainly for lead control, but will also fully optimize

the system for copper control under the current LCR. The treatment strategy discussed in this section is

supported by a blending analysis and hydraulic modeling to assure that optimal water quality parameters

can be met.

5.1 Optimal Level for pH Based on the solubility analysis, Confluence recommended the following water quality treatment goal:

Optimal corrosion control treatment for lead is achieved at pH ≥ 7.0 in the distribution

system.

Optimal corrosion control treatment will be reached when each wellsite selected for pH adjustment

treatment achieves a minimum pH of 7.4 at the entry point. Confluence did not recommend specific

targets for alkalinity, noting that source wells have adequate alkalinity and do not need alkalinity

adjustment.

5.2 Treatment Strategy Lacey’s strategy for optimizing corrosion control treatment is to use a prioritized, step-wise approach that

targets Lacey’s most corrosive sources first for installation of treatment, followed by large sources that

can increase pH throughout large areas of the system. Treatment is proposed at the following sources, in

the following order:

1. Increase the caustic feed at source S04, to raise pH to 7.6. The treatment facility has sufficient

capacity to increase the dose, and the City started implementing this recommendation in

September 2018.

2. Install pH adjustment treatment to increase entry point pH to 7.4 -7.6 at the following sources:

a. Beachcrest wells (wellfield source S17). This will include sources S15, S16 and the new

Beachcrest replacement well that is currently in construction. Adding treatment to these

wells will address the most corrosive sources that supply the system at this time.

b. College street wells 1, 2 and 3 (sources S01 and S18). Lacey is planning to drill a

replacement well for Source S01 in 2020, so adding treatment at this site will coincide

with construction of the new well.

c. Madrona wells 1, 2 and 3 (sources S23 and S28). These wells have the largest capacity

to supply the water system. These are large capacity wells that supply both the 400 and

337 pressure zones, and blend within a significant portion of the system.

27

This treatment strategy considers the complexity of the Lacey water system, the likely level of

improvement in water quality with additional treatment, spatial distribution of the wells, and plans for

additional supply and investments. Due to the significant amount of blending that occurs in the Lacey

system, Confluence did not recommend treatment at all sources, particularly lower capacity sources S06

and S20, and did not recommend treatment at source S29, which is not corrosive to lead. Another

consideration for treatment is that Lacey is still a growing system and is planning system improvements

(e.g., new reservoirs, and piping connections) that will increase the use of treated sources in the future,

and should increase blending in the system. Consequently, monitoring at customer taps and in the

distribution will be an important element of the Action Plan for determining whether additional source

treatment will be needed in the future. Monitoring will also support any needed changes that may need to

be made when the Long-Term Lead and Copper Rule revisions are adopted. The Action Plan and

monitoring are discussed in Section 6.

5.2.1 Blending Analyses and Hydraulic Modeling As noted in Section 4.2, source S04 is already treated, and sources S07, S09, S10 and S32 do not require

treatment. Because the treatment strategy does not propose treatment at sources S06, S20, S24, S25, or

S27, Confluence completed a blending analysis to evaluate expected pH in the distribution system when

untreated sources blend with noncorrosive and/or treated sources. The pH targets include pH ≥7.0, to

meet the requirements of the current LCR, and pH ≥ 7.2, which is anticipated to be a target for future

revisions in the LT-LCR. The focus of the analysis was on sources S06 (Judd Hill), S24/S25 (Nisqually

wells), S20 (McAllister) and S27 (Evergreen Estates), which all have pH < 7.0. The complete blending

analysis is within Appendix A of Confluence (2018).

To illustrate how treatment and blending can be used to meet the water goal throughout the system, and

particularly at Tier One sites, Confluence graphed optimal blending ratios needed to meet pH ≥ 7.0 under

a treatment scenario whereby sources S01/S18, S23/S28, and S27 are treated to a pH endpoint of 7.4.

Lacey’s hydraulic model was then used to assess where blending occurs in the system (Fig 9a), and to

what extent the optimal blending ratios can be met by adding treatment to sources (Fig 9b). After the

proposed treatments are installed, pH is predicted to be ≥ 7.0 throughout most of the distribution system,

with two exceptions: the 188 pressure zone (supplied by wells S24 and S25), and a small area in the 400

zone that is supplied primarily by source S20. The blending analyses for sources S06, S24/ S25, S20 and

S27 are discussed below.

5.2.1.1 Blending Zone for Source S06 The blending analysis completed for S06 is shown below in Figure 8. The analysis shows that pH ≥7.0

can be maintained by blending untreated S06 water with uncorrosive or treated sources, as long as the

blends contain ≤ 75% S06 water.

28

Figure 8. Expected pH at different blending levels near Source 6 (Judd Hill) Source: Confluence (2018)

Hydraulic modeling showed that these blends can be easily accommodated under current summer

operating scenarios (Figure 9b). The amount of supply provided by S06 is shown in Figure 2 and Table

3; both show that S06 does not provide a lot of supply to the water system, particularly during winter

months. The limited source of influence of S06 is evident in water quality parameter samples collected at

sample stand SS02, located just east of source S06 (Figure 3). The average pH at SS02 during 2017-2018

was 7.3, which indicates blending with noncorrosive source S07.

Based on the blending analysis and hydraulic modeling, and very low production, S06 is not

recommended for treatment. However, the Action Plan (discussed in Section 6) recommends adding a

water quality parameter monitoring location in the blending zone of S06 to verify that the treatment goal

is being met after treatments are installed.

Page 29

Figures 9a and 9b. Maps of Hydraulic Modeling Under Summer Operation (9a left: Blending under Current Conditions; 9b right: Predicted areas above, and below pH 7 after Treatment Installation)

30

5.2.1.2 Sources S24/S25 “Hot Spot” Analysis for 188 Pressure Zone

A “hot spot” analysis approach was used to evaluate the long-term impact of providing untreated S24 and

S25 water at customer’s taps, and to support a decision to not add corrosion control treatment on sources

S24 and S25.

The 188 pressure zone is a good candidate for this analysis, since there has been little change in the

source of supply, and residences served, for over 20 years. Also, there is a period of record of LCR tap

samples that have been collected in the 188 pressure zone since 1993.

Sources S24 and S25 have always been the main source of supply to this part of the water system. Both

wells are pumped every month, but S25 is the main source, supplying 70-80% of the demand. The area is

a non-expanding part of the Lacey water system, due to Thurston County regulations that limit

development within the flood plain of the Nisqually River. As a result, Lacey’s 2013 Water System

Comprehensive Plan projected 0% growth for single family, multi-family, and commercial connections

from 2008 – 2030. According to the Water Comprehensive Plan, in 2011 there were 241 water

connections in the 188 pressure zone, which at the time represented 1% of the total number of

connections supplied by the Lacey Water system and 1.4% of the ERUs. These percentages were used to

justify the sample size evaluated for the Hot Spot Analysis.

As shown in Table 7, there have been six rounds of LCR sampling with ≥ 5 samples collected. This is an

adequate sample size to evaluate the 188 zone, since during these years the entire Lacey water system was

required to collect at least 30 samples under its reduced monitoring schedule. Meaning, samples collected

from the 188 zone in 2002, 2005, 2008 and 2011 comprised over 15% of the total system sample pool,

but represented approximately 1% of the total population served.

The 90th percentiles for both lead and copper were below Action Levels. When compared to 90th

percentiles for the entire system, the 188 pressure zone had comparable 90th percentiles for lead, and

lower 90th percentiles for copper. Of 63 samples collected since 1993, the only samples > 0.015 mg/L

(three total) were collected during the 1993 and 1995 sample rounds.

Table 7. Summary of LCR samples collected within the 188 pressure zone

188 zone System

LCR yr n max Pb (mg/L)

90 %ile Pb (mg/L)

max Cu (mg/L)

90 %ile Cu (mg/L)

90 %ile Pb (mg/L)

90th %ile Cu (mg/L)

2014 2 0.011 NA 0.46 NA 0.006 0.86

2011 5 0.004 0.004 0.45 0.45 0.004 0.84

2008 5 0.003 0.003 0.42 0.42 0.008 0.96

2005 5 0.003 0.003 0.46 0.46 0.004 0.95

2002 6 0.012 0.008 0.63 0.13 0.008 0.92

1997 10 0.005 0.003 0.69 0.25 <0.002 0.50

1995 10 0.019 0.010 0.22 0.03 0.003 0.70

1993 20 0.018 0.011 0.29 0.12 not sampled

31

In 2011, LCR tap samples were collected on September 20, 2011. Water quality samples were collected

from sources S24 and S25, and at sample station #55 in the 188 zone, on October 5, 2011. These samples

were collected to support Lacey’s 2014 Corrosion Control Study, and illustrate water quality at the time

the LCR tap samples were collected (Table 8).

Table 8. Water quality in 188 PZ when 2011 LCR samples collected

Site Date pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3)

Temp °C

Calcium (mg/L)

Chloride (mg/L)

Sulfate (mg/L)

Avg pH, 2011, 2017-20181

S24 10/4/2011 7.14 52.8 52.0 11.6 41.0 6 4 7.11

S25 10/4/2011 6.92 58.0 61.2 11.4 30.0 6 3 6.90

SS55 10/5/2011 7.04 56.0 47.6 14.8 32 6 3 6.97 1 from quarterly samples results in Appendices C and D.

The pH results from each of the sites are no different from average results from quarterly samples

collected in 2011, and 2017-2018 (Appendices C and D).

Overall, the history of LCR tap sample results show that there is little risk of exceeding Action Levels in

the 188 zone when not adding treatment to sources S24 and S25. Consequently, treatment is not

recommended at this time to meet the current Lead and Copper Rule.

5.2.1.3 Blending Zone for Source S20

Blending ratios for S20 were evaluated for blending with treated sources S23/S28 (the Madrona wells),

and considered blending occurring within Lacey’s Steilacoom and Union Mills reservoirs. Blends of S20

with the Madrona wells represent current operations in summer/higher demand periods, when the

Madrona wells are used more.

Blending S20 with the Madrona wells treated to pH 7.4 is shown in Figure 10. The blending analysis

shows that pH ≥7.0 can be maintained as long as the blends contain ≤ 90% S20 water, or at least 10%

treated water from the Madrona wells. Figure 11 shows where these blends occur, based on hydraulic

modeling of areas receiving >90% S20 water (shown in red). Figure 9b also shows that the area where

blending will not achieve pH ≥ 7.0 can be reduced by piping improvements proposed by the City. The

reduced area (shown in orange) does not include any Tier One homes; most homes were constructed after

2000. Another consideration for source S20 is that it has a relatively small water right that is being fully

exercised, so blends containing S20 water are not expected to increase, and actually should decrease over

time.

The conclusion from the analysis is that untreated S20 water presents very low risk to Tier One homes, so

treatment is not recommended for source S20. However, this conclusion will be verified through the

monitoring proposed in Section 6.

32

Figure 10. Expected pH at different blending levels for McAllister (S20) and treated Madrona (S23/28)

5.2.1.4 Blending Zone for Source S27

Ratios for blending untreated S27 water with treated sources S23/S28 (the Madrona wells) is expected to

be the same as for S20, since water quality at both sources is very similar. Consequently, pH ≥7.0 can be

maintained as long as the blends contain <90% S27 water (or S27 combined with S20), i.e., blends

contain at least 10% treated water from the Madrona wells. Figure 11 shows where hydraulic modeling

predicts that pH will be < 7.0 if both S27 and S20 are untreated. This area does not include any Tier One

homes.

The hydraulic modeling analysis was based on current operations, but operating conditions are expected

to change due to growth in water demand and planned system improvements. Primarily, blends with

treated water from the Madrona wells are expected to consist of larger percentages of Madrona well water

as demand and system improvements allow greater use of the Madrona wells during winter months.

Consequently, as conditions change in the system it may not be necessary to add treatment onto S27, but

the need will be determined by tap sampling conducted after treatment is installed at the Madrona wells.

With this in mind, the Action Plan (Section 6) includes water quality parameter monitoring within the

impact zone(s) of S20 and S27, and pre-designing treatment for S27 if needed in the future.

33

Figure 11. Predicted pH with source treatment at S17, S01/S18, S23/S28

5.3 Available pH Treatment Methods

Lacey’s 2014 Corrosion Control Study evaluated all required corrosion control methods and eliminated

all from consideration except pH adjustment using caustic soda or aeration. Please see the 2014 study for

detailed discussions on treatment evaluation. For this study, Confluence (2018) evaluated available

treatment methods – primarily passivation through pH/alkalinity adjustment and passivation through use

of inhibitors – based on updated information in the EPA Revised Corrosion Control Treatment Guidance

Manual (USEPA 2016) and current industry practices. Confluence did not recommend using

orthophosphate inhibitors because pH adjustment of sources to pH 7.2-7.8 would be required anyway for

orthophosphate inhibitors to be effective. But, based on the ranges of pH and DIC of Lacey sources,

treatment options for reducing copper corrosion for source with pH less than 7.2. and DIC of 5-35 mg/L

as C is to raise pH using potash, caustic soda, silicates, or aeration (USEPA 2016; Confluence 2018).

34

Lacey has caustic soda treatment at S04 and is familiar with its use. Advantages associated with caustic

are, 1) the relatively low capital costs compared with aeration, 2) caustic dosing is relatively easy to

adjust to different treatment end points, and 3) caustic would not significantly increase the alkalinity of

the already fairly high alkalinity sources. However, the major downside to caustic soda is that it is a

hazardous chemical requiring safety measures in the treatment plant to prevent exposure to the operators

and accidental overfeed. Additional downsides include costs associated with operation and maintenance

and rising costs of caustic product. Whereas soda ash or potash are not needed because Lacey source

wells do not need alkalinity adjustment, Confluence noted that these could be used in lieu of caustic soda.

Aeration is used successfully by the Cities of Olympia and Tumwater, and consequently is being

considered for Lacey’s sources. Aeration is in an attractive option because it does not add chemicals to

the water and is safer to operate and maintain, and potentially will have lower lifecycle operations and

maintenance costs. Confluence noted that aeration would be the most appropriate treatment strategy for

higher DIC wells such as the Beachcrest wells. But, Confluence noted that a downside of aeration

systems is that there is less flexibility to adjust pH endpoints, and there will be a limitation on the upper

pH endpoints that can be achieved. Confluence estimated the percent carbon dioxide removals that would

be needed to achieve pH 7.4 at the entry point for all the corrosive supplies, and found that aeration would

need to strip 60-70% of the carbon dioxide. A higher pH endpoint than 7.4 may not be feasible for all

sources.

5.3.1 Source S04

Source S04 is currently treated with 25% caustic soda and at the time OWQP and LCR tap samples were

collected in 2017-2018, S04 was treated to pH 7.4 at the entry point. The well is operated at a maximum

pumping capacity of 750 gpm, and since caustic treatment was installed, the well has produced an average

of 158.7 MG per year. The proposed adjustment to treatment is to increase the current dose to achieve a

pH of 7.6 at the entry point. This change was implemented in September 2018.

Increasing the dose to increase pH at S04 was easily accommodated using existing equipment with minor

operational modifications. The treatment facility was originally sized for a larger capacity than currently

available at the site, and there is additional metering pump capacity to increase the dose further if needed.

There are three 1000-gallon tanks on site for storing caustic soda. The city currently gets monthly

deliveries and uses an average of 1,500 gallons/month. Increasing the pH endpoint to 7.6 was estimated

to increase chemical usage by about 135 gallons per month.

5.3.2 Sources S17, S01/S18, and S23/S28 Confluence recommends pH adjustment at these sources, and modeled planning level treatment estimates

for the Group 2, 3, and 5 wells (i.e., all corrosive sources) using caustic soda, soda ash, and aeration. For

each method, Confluence modeled chemical dosages or aeration needed to achieve pH 7.4, and to achieve

the “upper limit” of pH that can be achieved without causing calcium carbonate precipitation. All three

of these treatment methods are viable for treating sources S17, S01/S18 and S23/S28, and will be

considered in more depth during the pre-design phase of the facilities.

35

6.0 ACTION PLAN This Action Plan addresses the schedule for implementation, and processes to be followed for using

monitoring data to confirm when treatment is optimized. Possible next steps for actions or additional are

also included here.

In summary, this Action Plan includes the following:

A schedule for the sequential approach to installing corrosion control treatment in the Lacey

water system, starting with the most corrosive sources.

A monitoring approach for collecting distribution tap samples and customer tap samples.

A process for evaluating monitoring results to assess when treatment is optimized, and possible

next steps, if warranted by the monitoring results, to meet current LCR requirements.

Considerations for revisions to the LCR relating to new copper surfaces.

6.1 Schedule for Treatment Installation The schedule and approach to treatment is based on sequential addition of treatment facilities to achieve

pH ≥ 7.0 in the distribution system. The schedule, shown in Table 9, addresses the more corrosive

sources first, i.e., S01 and S17, but considers that the City has been planning to drill new replacement

wells at both the S17 and S01 well sites, and the new wells need to be constructed and tested for yield and

water quality characteristics in order to design appropriate treatment facilities. Note that the schedule for

installing treatment at S23/S28 includes two additional years for land acquisition to be able to

accommodate a new facility at the well site.

Table 9. Schedule for Installing OCCT

Year S04 S17 S18/S01 S23/S28

2018 Increase caustic

dose to 7.6

2019 Pre-design1 Pre-design Pre-design

2020 Design Drill S01 replacement well2 Design/Land Acquisition

2021 Construction Design Design/Land Acquisition

2022 Startup Construction Design/Land Acquisition

2023

Startup Construction

2024 Startup

2025

Collect tap samples & Identify OWQPs for

sources 1 Replacement well for S15 drilled late 2018, currently in construction

2 Replacement well for S01 is anticipated to be approved as part of wellfield S18

36

6.2 Monitoring The Department of Health has requested that when Lacey submits its Project Report for treatment

installation at sources S23/S28, the report should include a Sampling Plan that addresses

distribution OWQP tap sampling, customer tap sampling for lead and copper, and entry point

OWQP sampling. The Department will then request that the City recommend Optimal Water

Quality Parameters for all entry points, and after that the Department will assign OWQPs and

Lacey’s monitoring requirements for determining compliance with optimal corrosion control

treatment. The following monitoring steps include baseline monitoring to help evaluate blending assumptions and

treatment effectiveness as the three facilities come online, as well as considerations for entry point,

distribution and customer tap monitoring that will be required after treatment is installed.

6.2.1 Distribution Monitoring Before OCCT Installed

Baseline monitoring for water quality parameters (WQPs) will start in 2019, and will determine baseline

conditions throughout the system, especially in blending areas of sources that will remain untreated under

this Action Plan.

In addition to the twelve (12) distribution sites sampled for this study (see Table 5 and Figure 3),

distribution sample locations will be added in the following areas:

S06 (Judd Hill) – in blending zone with S18

S20 - in blending zone with Madrona wells

S27 – in blending zone with Madrona and Union Mills reservoir (337 zone blended water).

Nisqually

Confluence (2018) recommended collecting distribution samples quarterly, for the following parameters:

pH, temperature, alkalinity, and conductivity.

After OCCT Installed

After the third treatment facility is installed (at sources S23/S28), the frequency of distribution monitoring

will be increased to monthly to determine the effectiveness of achieving the goal of at least pH 7.0 in the

distribution system blending zones. Samples will be collected for pH, alkalinity, and conductivity.

This robust data set will be used by Lacey to recommend optimal water quality parameters (OWQPs) for

each source, i.e., the minimum pH at the entry point of each source once treatment is optimized for the

system.

6.2.2 Customer Tap Sampling

Customer tap samples will be collected in 2025, after the third treatment system is installed (at source

S23/S28) and treatment systems at S17, S01/S18 and S23/S28 have been operational and meeting entry

point targets for at least 4-6 months. Based on the current LCR requirements, sampling will consist of

two consecutive 6-month rounds of LCR tap monitoring that prioritize Tier 1 homes. Sampling may need

37

to be modified to comply with sampling and schedule revisions in the LT-LCR. Results of tap samples

will be evaluated using the process shown in Figure 12. Figure 12 provides a process for determining

whether treatment is optimized under the current Lead and Copper Rule, and next steps to take if Action

Levels, or the water quality target, are not met.

6.2.3 Entry Point Monitoring

Monitoring at all entry points (including untreated sources) is required after treatments are installed.

Biweekly monitoring, at a minimum, will be required at entry points for pH and chemical dosing (if

applicable). However, more frequent monitoring, even in-line monitoring, is recommended to more

closely track treatment and to minimize the potential for incurring treatment technique violations.

Violations are determined as a function of the frequency of monitoring, so more frequent monitoring

allows for more timely correction of drifting or outlier results.

Rather than monitoring all entry points, Lacey anticipates reducing the number of sites that will be

monitored by identifying representative entry points for untreated sources that have similar water quality.

In-line monitoring analyzers will be installed at all treated sources. Ideally, in-line analyzers will be

installed at the representative untreated sources at least one year before OWQP monitoring requirements

take effect.

6.3 Evaluation Process for Optimization

Figure 12 provides a process for determining whether treatment is optimized under the current Lead and

Copper Rule, and next steps to take if Action Levels, or the water quality target, are not met. This process

is applicable to the current LCR, but will likely need to be re-evaluated according to requirements of the

revised LCR after the LT-LCR is adopted.

Ultimately, customer tap samples will indicate whether additional treatment needs to be added to the

system. The City is proactively planning to predesign treatment for source S27, in case customer tap

samples exceed Action Limits and treatment must be installed within a Federally mandated timeframe.

However, this is not anticipated to be necessary since the system has been in compliance with Action

Levels since the Lead and Copper Rule was enacted.

Distribution monitoring results will indicate whether blending meets the water quality target within

blending zones for untreated sources S06, S20 and S27. If pH in the distribution is < 7.0 in any of these

blending zones, Figure 12 identifies next steps, including operational changes to improve CCT.

Operational changes may include the following:

increasing pH at entry points

changing call orders to increase amount of treated water entering the distribution system

changing settings on pressure reducing valves to promote

As shown in Figure 12, if Action Levels continue to be met but pH targets are not met within the

distribution system, the City may choose to conduct a Hot Spot analysis within the impact zone(s) that are

not meeting pH ≥7.0. The city will coordinate with the Department on the design of a hot spot analysis,

particularly in blending zones that have few, if any, Tier One homes.

38

Figure 12. Flowchart for Evaluating Tap Monitoring Results

Yes No

Pb ≤ 0.005 mg/L Cu ≤ 1.30 mg/L

Pb 0.006-0.015 mg/L Cu ≤ 1.30 mg/L

AL exceeded

b(3) Criteria Met, System Optimized

Identify what

changed

WQPs within optimal range?

Identify Risk Areas

System Optimized Increase Treatment Levels if Possible

Complete Investigative Tap Sampling Following DOH’s Hot Spot Approach. If the

issue is Copper, then prioritize on new construction

Evaluate Alternative Operational Strategies to Increase the Proportion of Non-Corrosive or

Treated Sources to the Area

Pb ≤ 0.015 mg/L Cu ≤ 1.30 mg/L

System Optimized Pb/Cu ≥ AL

Install Treatment to the source(s) supplying the

area

90th percentile of LCR Tap Samples

39

6.4 Considerations for Revisions to the LCR

For several years, EPA has been developing revisions to the LCR that include regulatory options for

improving the existing rule to strengthen public health protection and to clarify implementation.

Revisions are still in the process of being considered, and the schedule for updating the rule has been

delayed several times. The current timeframe projects that a public review draft will be released

sometime in 2019. While issues with the existing rule have been identified, there is still uncertainty

regarding which issues will be addressed in the revisions and, more to the point, the specific requirements

that will be associated with them. Dates for implementation will also be identified in the revisions.

6.4.1 Approach and Recommendations for Revisions Relating to New Copper Surfaces

Anticipated revisions to the Rule include isolating and separating lead and copper tap monitoring, and

may include monitoring sites with new copper installations. Revisions that address new copper surfaces

could require increasing the water quality target for optimizing treatment in the Lacey water system, since

solubility analysis (Section 4.2) identified several sources that are corrosive to new copper surfaces.

Confluence recommended a water quality goal of pH ≥ 7.2 in the distribution system for protecting new

copper surfaces. However, as noted earlier, at this time copper is not the material of choice for new

development in Lacey, so it may be necessary to conduct a materials analyses within impact areas that do

not meet pH ≥ 7.2 to evaluate whether copper plumbing is present. This will be particularly important

within the 400 zone, where most new development is occurring and where blending analyses showed that

pH ≥ 7.2 may not be met in the vicinity of untreated sources S20 and S27. If additional treatment appears

to be warranted to increase pH in the 400 pressure zone, source S27 (Evergreen Estates) was identified as

a potential for treatment because it has a larger pumping capacity, and a larger water right, than source

S20. Lacey plans to pre-design treatment for S27 while the other sources are in pre-design, but will hold

on to the plans while monitoring is occurring following treatment at sources S23/S28.

40

References

City of Lacey, 2014. City of Lacey Corrosion Control Evaluation Final Report. March 2014.

Confluence Engineering Group, LLC. 2018. pH Treatment Recommendations, Water Quality Consultant

Project Task 1, December 28, 2018.

HDR, 2007. City of Lacey Well 4 Final Treatment Process Selection Report. January 2007.

RH2 Engineering, 2018. Wells Nos. 1, 2, and 3, Well No. 4, and Madrona Wells pH Adjustment

Facilities. Technical Memorandum July 13, 2018.

Sandvig, A.M., 2009. Non-leaded brass—A summary of performance and costs. Journal AWWA,

101:7:83.

USEPA. 2016. Optimal Corrosion Control Treatment Evaluation Technical Recommendations for

Primary Agencies and Public Water Systems. EPA 816-B-16-003. March 2016.

Washington State Department of Health, 2009. Water System Design Manual. DOH 331-123 (Rev.

12/09).

Xiao, W., S. Hong, Z. Tang, S., Seal, and J.S. Taylor, 2007. Effects of blending on surface characteristics

of copper corrosion products in drinking water distribution systems. Corrosion Science 49(2007)

449-468.

Zhang Y., and M. Edwards, 2011. Zinc content in brass and its influence on lead leaching. Journal

AWWA, 103:7:76.

41

Appendix A. 2017 from DOH Outlining OCCT Steps for Lacey

42

43

44

Appendix B. Technical Memorandum from Confluence Engineering Group, LLC (2018): pH Treatment Recommendations

Page 1

To: Puna Lovell, City of Lacey

Subject: FINAL - pH Treatment Recommendations

From: Virpi Salo-Zieman, PE Melinda Friedman, PE Stephen Booth, Ph.D, PE Danbi Won, EIT

Project: Water Quality Consultant Project, Task 1 Amendment 1

CC: Julie Rector, City of Lacey Date: December 28th, 2018

CONTENTS 1. Introduction .......................................................................................................................................... 1

2. Background ........................................................................................................................................... 1

3. Literature Review .................................................................................................................................. 1

3.1. The Role of Scales ............................................................................................................................. 2

3.2. Optimal Corrosion Control Treatment (OCCT) Strategies ................................................................. 3

3.3. Potential Long Term LCR Revisions (LT-LCR) ..................................................................................... 4

4. City of Lacey Water Quality Evaluation ................................................................................................. 7

4.1. Lead and Copper Tap Samples .......................................................................................................... 7

4.2. Solubility Modeling ........................................................................................................................... 7

4.3. Distribution System Water Quality ................................................................................................. 12

5. Treatment Evaluation ......................................................................................................................... 14

5.1. Point of Entry Optimal Water Quality Parameters (OWQPs) – Existing LCR .................................. 15

5.2. Point of Entry OWQPs – Future LT-LCR ........................................................................................... 15

5.3. Distribution System OWQPs – Existing LCR .................................................................................... 16

5.4. Distribution System OWQPs – Future LT-LCR ................................................................................. 17

5.5. Chemical Selection and Dosing ....................................................................................................... 17

5.6. Additional Water Quality Considerations ....................................................................................... 20

6. Summary of Findings and Recommendations .................................................................................... 20

References .................................................................................................................................................. 22

Appendix A – Blending Analysis .................................................................................................................. 23

Appendix B – Action Plan ............................................................................................................................ 23

Appendix C - Planning Level Cost Estimates for Caustic Soda pH Adjustment Facilities (RH2 Engineering) .................................................................................................................................................................... 23

Page 1

1. Introduction

The City of Lacey (City) contracted with Confluence Engineering Group, LLC to develop an optimal corrosion control plan for the City. The objective of this Task is to evaluate Lacey’s current water quality against the drinking water industry’s current understanding of optimal corrosion control and determine if adjustments are needed. The evaluation considered the following:

Current water quality and treatment conditions

Existing Lead and Copper Rule (LCR) requirements, which drive the basis for optimization recommendations in this report

Impacts of possible long-term revisions to the LCR (LT-LCR) and future optimization considerations

Key recent literature and generally accepted industry practices

Lead and copper solubility theory

2. Background

According to City’s Water Resources staff:

Lacey’s service population increased above 50,000 people and therefore, the water system is now considered a large system under the LCR.

As a large system, the City must complete a corrosion control study and provide optimal corrosion control

Since the previous study (completed in 2014), the City has stopped purchasing water from the City of Olympia, which used to provide close to 30% of the total supply. Other changes include inactivation of Source 1 (Well 1) and addition of a new source (S31) in the Hawks Prairie wellfield. Well 1 is scheduled for replacement in the future. The City has also made upgrades that allow for expanded use of the Madrona wells (S21, S22, S28).

During 2016 and 2017, Lacey collected two standard monitoring sets of lead and copper tap samples with a goal to qualify for the “b(3)” exemption (40 CFR 141.81(b)(3)) that would have deemed the system optimized for corrosion control without further steps. The results from these two sets showed that the City continues to meet both action levels, but only met the “b(3)” 90th percentile Practical Quantitation Level criteria of 0.005 mg/L for lead in one of the two sample rounds (the 90th percentile lead levels for 2016 and 2017 were 0.006 mg/L and 0.005 mg/L, respectively). Therefore, this corrosion control evaluation was required and the City needs to have optimal water quality parameters assigned.

3. Literature Review

When the LCR was first promulgated in 1991, EPA established maximum contaminant level goals (MCLGs) of zero for lead and 1.3 mg/L for copper. While the rule has been revised several times and corrosion theory has evolved, these goals have not changed indicating them being adequately protective of public health. Significant changes in the corrosion theory relate to lead corrosion and optimal corrosion control treatment (OCCT). Advances have also been made in understanding factors impacting copper corrosion. Current industry knowledge of corrosion as it relates to the City’s water system is summarized below.

Page 2

3.1. The Role of Scales

The scales that have formed on the pipe surfaces over time control the effectiveness of (and ability to optimize) corrosion control treatment. The scales can be complex, layered, and impacted by the water quality the pipe has been exposed to in the past. The scales are considered to be either passivating films that are formed when the pipe material and water react directly with each other, or deposits of precipitated or otherwise sorbed compounds (EPA 2016).

The characteristics of the scale and its structure determines how much metal could be released into the water. The most desirable conditions support the formation of insoluble and adherent scales such as lead and copper oxides. Soluble and less adherent scales tend to release more metals. Releases can also be expected with changing water quality conditions when the scales are trying to reach a new equilibrium.

Lead pipe scales are typically dominated by hydrocerussite (Pb(II)3(CO3)2(OH)2) or cerussite (Pb(II)CO3), which are both Pb(II) -carbonate compounds. Under highly oxidizing conditions, lead oxide, a Pb(IV)-compound, can form and become the dominant mineral. Copper-based scales are typically cuprite (Cu(I)2O), cupric hydroxide (Cu(II)(OH)2, tenorite (Cu(II)O), and malachite (Cu(II)2(OH)2CO3). When orthophosphate is used, these metals tend to form various phosphate scales (EPA 2016). The presence of other metals such as aluminum, iron or manganese, calcium, or organic matter will also influence the type and properties of the scales that form.

Solubility models predict the metal solubility from the scale in equilibrium with the water. It is important to note that theoretical models generally tend to over-predict soluble concentrations, and therefore, can be considered conservative. Because they do not predict absolute values, they should be used to evaluate likely trends in solubility, rather than actual metals concentrations presented on the y-axis. Additional limitations with use of theoretical models include:

Models assume conditions at equilibrium

o The time component to reach equilibrium under varying distribution system water quality conditions is not known.

o Frequent changes between significantly different source water qualities, such as low DIC surface waters and high DIC groundwaters, likely prevent equilibrium from being reached.

Models represent specific chemistry conditions

o Real world distribution system conditions vary considerably seasonally, spatially, etc.

o Models do not consider impacts of competing ions, or other chemical, physical, and microbial conditions that affect scale formation and stability in distribution systems.

Pb(II) and Cu(I/II) Solubility

Figure 1 shows the classical pH/alkalinity diagrams for lead and copper solubilities developed by Schock and Lytle (2011). These diagrams show lead and copper solubility as a function of pH and DIC, for a wide range of DIC conditions. These indicate that at pH of less than 8, increasing DIC generally lowers lead solubility, while around pH 8, lead solubility flattens out for some DIC conditions, and then there is a flip-flop, where increasing DIC causes increased lead solubility. Copper solubility tends to decrease with decreasing DIC at any pH level and generally with increasing pH.

Copper solubility and release due to uniform corrosion in the system is not only related to the water quality characteristics and conditions (pH, DIC, ORP), but also to the aging process of the pipe materials and scales. According to Schock and Lytle (2011), in the most ideal case, uniform corrosion of copper is

Page 3

inhibited by the formation of a duplex film consisting of a layer of cuprite, Cu2O, underneath a layer of either tenorite or malachite. While these layers will theoretically form under equilibrium conditions, the process can take years, even decades, and includes intermediary steps with more or less stable and soluble compounds (such as cupric hydroxide solids (Schock and Lytle 2011)). More research is needed to understand the complex chemistry of aqueous copper and potential public health implications. As discussed below, revisions to the LCR may require additional sampling at newer copper installations. Although plumbing materials present in the City’s water system are at different stages of aging and experience different dominant scale types, a conservative approach for considering compliance with the LT-LCR would be to assume fresh copper surfaces and the presence of cupric hydroxide, the more soluble intermediate copper scale.

Figure 1. Lead and Copper Solubility as a Function of pH for Varying DIC (Schock and Lytle, 2011, and 2018 webinar)

A similar solubility evaluation approach was used to evaluate the corrosive tendencies of the City’s source waters. The theoretical lead and copper solubilities were modelled under current water quality conditions using WaterPro_6.30 and are discussed in Section 4.

3.2. Optimal Corrosion Control Treatment (OCCT) Strategies

The current industry understanding of OCCT for lead and copper control has advanced into the following:

1) Passivation through pH/alkalinity adjustment

2) Passivation through use of phosphate- or silicate-based inhibitors

3) Formation of a Pb(IV) scale through maintenance of a high free chlorine residual/high oxidation-

reduction potential (ORP)

These OCCT strategies are all based on controlling soluble lead and copper. However, optimal corrosion

control treatment can also reduce particulate lead to some degree when stable scales are formed and

maintained. Calcium carbonate precipitation is no longer a recommended treatment technology for lead

and copper control since it has been found to be non-uniform across plumbing surfaces. Additional

information on these treatment strategies is provided in Table 1.

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Higher ORP, which is largely controlled by secondary disinfectant type and residual, impacts the formation

of lead (IV) scales, iron release, manganese release, and co-occurring lead present in iron and manganese-

rich scales. The role of microbial influenced corrosion can also be an important factor contributing to

metals release in distribution systems and premise plumbing (AWWA M58, 2017).

The lead and copper rule working group (LCRWG) has defined a range of water quality conditions that are considered corrosive to homes with new copper (Figure 2), since these conditions prevent passivation of new copper surfaces. Further or additional actions may be required when water quality falls within the shaded, corrosive area, as discussed in Section 5.

Figure 2. Conditions that are Corrosive to New Copper Surfaces as Defined by the Lead and Copper Rule Working Group (Roth et al., 2016)

3.3. Potential Long Term LCR Revisions (LT-LCR)

The LCR is undergoing revisions. In addition to potential changes to OCCT described above, other issues

with the current LCR may be addressed through the revision process. A series of stakeholder meetings

have been held over the past several years, and the following issues have been raised for consideration.

Some of these considerations are based directly on lessons learned from the developments in Flint,

Michigan:

EPA recognizes that the LCR is too complicated to comply with and enforce. A more prescriptive

regulation, with less discretion/judgment allotted to utilities and states is needed.

A more integrated approach to minimizing lead exposure is needed, considering contributions

from water, paint, soil, dust and other potential sources.

Proactive lead service line (including gooseneck) replacement programs may be required.

Clarifications of sampling requirements are needed, such as the recent directive prohibiting

flushing before stagnation period and use of narrow-mouthed bottles.

Need for increased optimal water quality parameter monitoring to verify process control.

Need to establish health-based, household action levels for lead.

Need for a health-based benchmark for lead (rather than action level) to communicate health risk.

Isolate and separate lead and copper issues.

Strengthen transparency and public education programs, particularly for at-risk populations.

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Specific requirements and the degree to which the items listed above will be included the LT-LCR are currently uncertain. The release date for the draft LT-LCR has been delayed several times. The current projection is that a draft will be released for public comment in 2019.

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Table 1 Overview of Corrosion Control Treatment Options (Source: Confluence Engineering Group Project Files)

Technique and Chemicals Used Benefits Challenges and Problems Calcium Carbonate Precipitation Potential (CCPP) Raise pH and adjust Calcium

Increase CCPP to 4-10 mg/L

Maintain positive Langelier Saturation Index.

Limited Poor/ineffective lead and copper corrosion control

Does not form uniform, non-porous passivated layer

Can have excessive precipitation and reduction in pipe capacities.

Carbonate Passivation

Raise pH and/or alkalinity

Various combinations of caustic soda, carbon dioxide, soda ash, sodium bicarbonate, and/or lime

Carbon dioxide stripping

Binds lead and copper by forming carbonate complexes

Suitable in lower-alkalinity water if adequate buffering capacity maintained

Creates beneficial pH conditions for stabilizing chloramine residual (where used)

Does not add nutrients to water

Can cause CCPP in hard waters (white precipitate)

Significant fluctuations in pH and DIC (e.g. surface water vs groundwater) can cause lead-carbonate to dissolve, porous scales, particulate lead

May require multiple chemical additions to hit specific pH/alkalinity/DIC targets in low alkalinity waters

Some alkalinity-adjustment chemical feed systems (solids/powders) can be difficult to operate

Inhibitor Addition

Phosphate addition (using zinc orthophosphate, phosphoric acid, or tripotassium phosphate)

Silicate addition (various percent concentrations and ratios)

Possibly requires only single chemical addition

Binds lead and copper by forming phosphate complexes

Possibly provides longer-lasting protection against intermittent fluctuations in treatment (e.g., blending with other waters, treatment interruption)

Effective over a range of water quality conditions

Polyphosphate is not effective for lead control

Silicate is very expensive and not used in larger applications

Silicates can raise pH of finished water

Orthophosphate effective over pH range 7.2-7.8

Increases downstream wastewater nutrient (and zinc, if used) loading

Nutrient loading may promote biofilm growth if disinfectant residual decreases, and will promote algae growth in exposed reservoirs

Insufficient dose can accelerate corrosion, and overdose can cause milky water

Nutrients may exacerbate microbially-influenced corrosion

Formation of Pb(IV) Scale

Use elevated free chlorine residual to favor formation of Pb(IV) scales

Pb (IV) scale is less soluble and more stable compared to Pb (II) scale formed under routine oxidation-reduction conditions

Can form increased disinfection by-products

Can result in increased customer taste and odor complaints

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4. City of Lacey Water Quality Evaluation

4.1. Lead and Copper Tap Samples

The history of lead and copper tap sample results were characterized in the City’s 2014 Corrosion Study and updated through 2017. In general, copper levels have decreased and lead levels have remained low. Table 2 presents the 90th percentiles for the compliance sample sets for the Lacey main system (excluding historical results of any satellite system like Beachcrest that have since been consolidated into the main system).

Table 2. Lead and Copper Tap Sample Results

Year Number of

tap samples

mg/L Lead mg/L Copper

90th percentile

Max result

90th percentile

Max result

1992 0.008 0.85

1995 0.003 0.70

1996 <0.002 0.50

1999 0.003 0.01 1.00 1.96

2002 0.008 0.012 0.92 1.8

2005 0.004 0.015 0.95 2.3

2008 0.008 0.010 0.96 1.4

2011 0.004 0.023 0.84 1.2

2014 0.006 0.011 0.86 1.2

2016 67 0.006 0.049 0.81 1.3

2017 63 0.005 0.019 0.69 1.1

Based on historical monitoring results, the system meets both action levels and therefore, by definition the City can be considered optimized for copper corrosion under the current rule and qualified for reduced monitoring. Yet the results show that copper levels are somewhat elevated, and if the LT-LCR were to separate copper sites from lead sites and require sampling from newer copper construction, further action to reduce copper corrosion may be required. Lead results are low indicating good lead control. In fact, the City failed to meet the “b(3)” definition of optimization by 0.001 mg/L in one of two full monitoring rounds (2016). Had the City met the b(3) criteria, no further treatment would be required for either lead or copper under the current LCR. However, if the future rule includes an individual household action level, further measures may be needed to address specific locations. The modeling scenarios in Section 4.2 help identify which wells would benefit most from additional treatment.

4.2. Solubility Modeling

The City has monitored water quality characteristics at entry points and at twelve sites in the distribution system on a quarterly basis in 2011 and approximately every two months starting July 2017. The medians of the available data at each entry point were used to evaluate the theoretical lead and copper solubility in thermodynamic equilibrium with the minerals predicted by the model (WaterPro_6.30) to be most prevalent in the scale. Table 3 summarizes the water quality for the currently active sources. Figure 3 shows the corresponding modeled lead and copper solubilities.

Because of the aging process of the copper scales, the modeling was completed for both cupric hydroxide (new surfaces) and malachite (aged surfaces). As shown in the figures, once malachite is formed, the copper solubility is significantly lower, and on the same scale as copper results measured by the City during LCR sampling. According to the City, the vast majority of copper within the City’s system is aged, since most new construction is using PEX plumbing, rather than copper plumbing materials. The dominant lead scale is predicted to be cerussite (Pb II) based on the water quality at the entry points. In areas where

Page 8

chlorine residuals are typically greater than 0.8-1.0 mg/L, it is possible that plattnerite (Pb (IV)) could form, further lowering soluble lead levels.

Table 3. Summary of Water Quality Characteristics used for Solubility Modeling at Each Entry Point 1

TDS pH Alkalinity Calcium Temp Chloride Sulfate DIC

S# Source Name mg/L s.u. mg/L as CaCO3 mg/L oC mg/L mg/L mg/L as C

S24 Nisqually 19a 69 7.10 55 37 11.8 6.0 4.0 16.1

S25 Nisqually 19c 70 6.93 59 36 11.5 6.0 3.0 18.5

S04 Well 4 96 7.38 72 42 12.9 0.0 11.0 19.1

S06 Well 6C; Judd Hill 93 6.89 76 47 12.3 6.0 12.0 24.4

S07 Well 7 102 7.43 83 52 11.1 8.0 12.0 21.9

S09 Well 9 59 7.66 43 25 11.2 7.0 6.0 10.9

S10 Well 10 83 7.51 64 47 11.3 7.0 11.0 16.7

S18 Well 2 & 3 100 6.89 82 52 12.6 6.0 7.0 26.2

S17 Beachcrest 132 6.99 98 80 12.1 10.0 10.0 29.9

S32 Hawks Prairie 57 7.61 40 21 11.5 8.5 2.0 10.2

S20 McAllister 97 6.98 67 55 11.5 7.0 8.0 20.5

S23 Madrona 1&2 92 6.98 66 54 14.2 7.0 8.0 19.9

S27 Evergreen 89 7.01 60 53 11.7 6.5 7.0 18.1

S28 Madrona 3 92 7.03 65 51 12.4 7.0 8.0 19.3

S29 Betti 181 7.15 140 116 11.8 23.0 10.0 39.8

1Median values were calculated from the available data (quarterly samples in 2011 and July – December 2017) for all other

parameters except the highest calcium concentration was selected as a more conservative measure.

Figure 3. Theoretical Lead (cerussite) and Copper (malachite and cupric hydroxide) Solubility at Each Entry Point

Based on solubility modeling (Figure 3), the most corrosive sources to fresh copper surfaces are S6, S17, and S18. To evaluate the impact of pH adjustment with caustic soda on lead and copper (new and aged)

Page 9

solubilities, the wells were grouped into categories based on pH and DIC. pH and DIC are the controlling variables for corrosion control when using carbonate passivation. The ranges of water quality for these groups are presented in Table 4. The ranges of chemistry in the City’s sources, specifically pH and DIC, behave differently for lead versus copper as described in Section 3.1 and shown in Figure 4 (a-c). Lead solubility tends to decrease with increasing DIC and pH until about pH 8, while copper solubility tends to decrease with decreasing DIC and increasing pH.

Table 4. Source Grouping under Current Treatment Conditions

Group Sources DIC mg/L as C

pH s.u.

TDS mg/L

Ca mg/L

ALK mg/L as CaCO3

G1 9, 32 10-11 7.6-7.7 57-59 21-25 40-43

G2 20,23,24,25,27,28 15-21 6.9-7.0 59-97 36-55 55-67

G3 4,7,10 17-22 7.4-7.5 83-102 42-52 64-83

G4 6,17,18 24-30 6.9-7.0 93-132 47-80 76-98

G5 29 40 7.15 181 116 140

Figure 4(a). Modeled lead solubilities. Stars indicate the water quality groups; S1 represents water

quality from the currently inactive Well 1.

Page 10

Figure 4 (b). Modeled copper solubilities in equilibrium with malachite (solid lines) and tenorite (dashed lines) representing aged surfaces and existing LCR. Blue line shows the copper action level.

Stars indicate the water quality groups; S1 represents water quality from the currently inactive Well 1.

Figure 4 (c). Modeled copper solubilities in equilibrium with cupric hydroxide representing new surfaces for potential LT-LCR . Blue line shows the copper action level. Stars indicate the water quality groups; S1 represents water quality from the currently inactive Well 1.

Page 11

The results from the solubility modeling with regard to the existing LCR and potential future LT-LCR are summarized below.

Existing LCR

1. Lead solubility (Figure 4a) is in good control for higher DIC wells as long as the pH is ≥ 7.0. Some additional benefit is obtained with increasing pH to 7.2, with only marginal benefit associated with raising the pH above 7.2. The exception is under low DIC conditions (≤ 10 mg/L C). The City’s sources with DIC of 10 mg/L C already have a median pH above 7.5 and are therefore optimized.

2. Aged copper surfaces (Figure 4b) show very low copper solubility with formation of malachite or tenorite. The City’s sources are optimized with regard to copper solubility under the existing LCR given compliance with the copper action level. However, marginal additional benefit could be realized by raising the pH ≥ 7.0, assuming some tenorite is present (dashed lines). If malachite (solid lines) is the dominant copper form in the scales, very little additional benefit is anticipated by raising the pH ≥ 7.0.

Future LT-LCR

1. As shown in Figure 4c, solubility of new copper surfaces (cupric hydroxide equilibrium) is predicted to significantly decrease until approximately pH 7.2, after which the degree of benefit begins to taper off, up to a pH of approximately 8.0.

2. The sources with combined higher DIC and low pH are the most corrosive to new copper surfaces.

o Betti well (G5), with a DIC 40 mg/L as C and pH of 7.2, is corrosive to new copper surfaces due to its high DIC. Given the elevated hardness, it would be difficult to raise the pH further without causing significant calcium carbonate precipitation issues. Blending Betti water with either Hawks Prairie or Madrona will reduce the DIC and the corrosivity.

o The Group 4 wells (Sources 6, 17, and 18), with DIC of about 30 mg/L as C and pH of 6.9-7.0 are also corrosive to new copper surfaces.

o There are two Groups (#2 and #3) with DIC of approximately 20 mg/L C. Sources 4, 7, and 10 (Group 3) already have entry point pH’s around 7.4 and therefore, would not be considered significantly corrosive to new copper. The Group 2 wells have pH from 6.9-7.1 and are considerably more corrosive to new copper surfaces.

o Source 4 already has caustic soda addition in place and in the interim, increasing the level of treatment at this source to pH 7.6 would likely off-set the lower pH of several of the sources in the area (Sources 1, 18, and 6). The water quality from the other sources that also serve this area (Sources 9, 7, and 10) are considered non-corrosive.

o Source 1 was not included in the above analysis because it was offline during the 2017-2018 timeline. The City has now indicated that this well may be rehabilitated or replaced and brought back to service. According to the 2011 data and the one sample that was completed in 2017, this source has a finished water pH of 6.7 and DIC of 26 mg/L as C, which indicates highly corrosive characteristics to new copper surfaces.

Page 12

4.3. Distribution System Water Quality

The City collects distribution system water quality parameter (WQP) samples from 12 sites covering all pressure zones. WQP sampling locations are shown as yellow triangles in Figure 5. City sources are shown as blue stars. LCR tap monitoring locations are shown as green and purple dots, with purple indicating a location with lead > 0.005 mg/L.

Page 13

Figure 5. Water System Map. Location of sources (blue stars); WQP sampling sites (yellow triangles); LCR tap sample locations (green and purple dots).

Page 14

Results from 2011, 2017, and 2018 sampling rounds are shown in Figure 6. The large pH increase between 2011 and 2017 is primarily due to discontinuation of the Olympia supply.

Figure 6. Median Distribution System pH (2011, 2017, and 2018)

The DIC in the distribution system (Figure 7) is mostly between 20-30 mg/L as C, consistent with the majority of City’s well supplies. The influence of low DIC Hawk’s Prairie Well can be seen on site 36 in the 400 zone, while the influence of the high DIC Betti Well is not noticeable in the medians of the data set.

Figure 7. Median Distribution System DIC (2011, 2017, and 2018)

5. Treatment Evaluation

The City’s water system is complex with multiple pressure zones and sources that draw from different aquifers and have variable water quality characteristics. The City’s LCR tap sample results indicate optimal conditions for copper under the existing LCR, and nearly optimal conditions for lead. Based on the 2017 supply records, about 34% of the total supply is already noncorrosive or does not require additional corrosion control treatment. Treatment recommendations summarized in this section consider this supply complexity, the likely level of improvement in water quality with additional treatment, spatial distribution

6.2

6.4

6.6

6.8

7.0

7.2

7.4

7.6

7 14 17 41 65 2 11 91 12 20 36 30 55 90

pH

Sample Site2011 Median pH 2017 Median pH 2018 Median pH

337 Pressure Zone 400 Pressure Zone 188Zone

224Zone

0

5

10

15

20

25

30

35

7 14 17 41 65 2 11 91 12 20 36 30 55 90

DIC

mg/

L as

C

Sample Site

2011 Median 2017 Median 2018 Median

400 Pressure Zone337 Pressure Zone 188Zone

224Zone

Page 15

of the wells, blending of wells, and future plans for additional supply and investments. It is not feasible or likely necessary to treat all active sources that might be corrosive to new copper surfaces when some sources serve built-out areas that are not zoned for new construction. Furthermore, according to the City’s Building Official, PEX started being used in the later 1990’s, and has been used in the majority of homes starting in 2005. It is now used almost exclusively in large developments. Therefore, the recommended approach includes prioritized and step-wise improvements that focus on optimizing corrosion control treatment to maximize public health protection associated with potential lead release, while also considering the need for enhanced copper control under a future, more stringent LT-LCR.

5.1. Point of Entry Optimal Water Quality Parameters (OWQPs) – Existing LCR

For the water quality characteristics of the City’s supply portfolio, optimal corrosion control treatment for the existing LCR is achieved at pH ≥ 7.0. Given the complexity of the City’s system and significant blending between sources, within reservoirs, and across pressure zones, not all sources will need treatment to reach pH ≥ 7.0 within the distribution system. pH ≥ 7.4 should be targeted for sources with existing treatment, those selected for future treatment, and any new wells that are brought on line in the future. Specific treatment recommendations are summarized below. Once treatment is installed as summarized below, the City’s portfolio of non-corrosive sources will increase from approximately 34% to approximately 84% of pumped capacity.

1. Increase the caustic feed to raise pH at Well 4 to 7.6. The treatment facility was sized for a larger supply capacity than currently available at the site. The City should also add supply capacity at this site to fully utilize the existing treatment.

2. Install pH adjustment treatment to increase the entry point pH to 7.4-7.6 at the following sources:

a. G2 Wells: i. Madrona Wells 1, 2, and 3 (S23 and S28). As large capacity wells, this would

benefit the 400 and 337 zones, and under some operating schemes, the 188 zone.

ii. Evergreen Estates (S27) to address the areas of new growth that may include newer copper plumbing and typical winter operating conditions.

b. G4 Wells: i. S18 in conjunction with replacing Well 1 (S1) which would result in pH increase

in 337 zone. ii. S17 in conjunction with replacement of one of the Beachcrest wells.

5.2. Point of Entry OWQPs – Future LT-LCR

The future LT-LCR may require sampling from homes with newer copper plumbing. As shown in Figure 8, raising the pH of Groups 2 and 4, as proposed above, would also shift these sources into the “noncorrosive” zone for new copper surfaces.

Page 16

Figure 8. Impact of Increasing pH of G2 and G4 Wells on Copper Corrosion

5.3. Distribution System OWQPs – Existing LCR

Some degree of blending will occur within the distribution system, raising the pH of a significant portion of the remaining 16% of untreated sources. A detailed blending analysis was conducted and results are shown in Appendix A, and used to support the recommendations below.

Key WQP recommendations for distribution system sites under the existing LCR include:

1. The pH within portions of the distribution system that serve Tier 1 homes (potentially containing leaded materials) should be maintained ≥ 7.0.

2. A few small areas will likely continue to receive untreated water. The City will attempt to minimize these areas over time through:

a. Operational modifications to enhance blending, b. Preferential source use, c. Increasing entry point pH for large producers (such as Madrona Wells), or d. Confirming through special monitoring and plumbing investigations that lead and

copper levels are below action levels (i.e., Hot Spot analysis).

Given the complexity of the system, a set of WQP Bins have been developed to visualize and track the anticipated impacts of treatment and blending, as shown in Figure 9. The overarching objective is to meet Bins 1 and 2, since they were developed to ensure optimal lead corrosion control, and should be beneficial under the existing and future LT-LCR.

An Action Plan (Appendix B) has been developed to describe water quality monitoring (including routine and investigative monitoring) that will help to understand the impact from each source and installed treatment over time. This information will be used by the City to determine if:

Optimization has been reached

Treatment at additional sources or modifications to existing treatment is needed, or

If other operational strategies should be implemented to ensure optimization under the current and future LT-LCR.

The Action Plan may need to be modified once the LT-LCR is published and in effect.

Page 17

Figure 9. Anticipated WQP Bins after Treatment Installation at S23&28, S18, S1, S17, and S27. (Note: if S27 is not treated, Bin 3 will also include areas that receive ≥ 50% S27).

5.4. Distribution System OWQPs – Future LT-LCR

1. The pH within portions of the distribution system that serve Tier 1 homes (potentially containing leaded materials) should be maintained ≥ 7.0.

2. The pH within the portions of the distribution system that are expanding and may have homes with newer copper plumbing should be maintained at ≥ 7.2. These areas should be identified through review of construction records combined with WQP monitoring after recommended treatments discussed in Section 5.1 are operational, in accordance with the City’s LCR Action Plan.

5.5. Chemical Selection and Dosing

Based on the EPA Revised Corrosion Control Treatment Guidance Manual (USEPA, 2016), the recommended treatment for reducing copper corrosion for source with pH less than 7.2 and DIC of 5-35 mg/L as C is to raise pH using potash, caustic soda, silicates, or aeration. Table 5 provides a summary of potential treatment strategies for all untreated sources (including increased caustic soda dosage at Well 4). Planning level cost estimates for treatment using caustic soda have been developed and are summarized in Appendix C. Cost estimates for soda ash and aeration are under development.

The City has caustic soda treatment in place at S04 and is familiar with its use. Caustic soda would not significantly increase the alkalinity of the already fairly high alkalinity sources and would be relatively easy to adjust to different treatment end points. However, caustic is a hazardous chemical requiring safety measures in the treatment plant to prevent exposure (operators) and accidental overfeed. The estimated

Page 18

dose to reach pH 7.4 and the maximum dose to avoid undesirable carbonate precipitation in the distribution system are presented in Table 5.

Aeration is typically the most appropriate strategy for higher DIC wells such as in the City’s Group 4 wells. The level of aeration needed to achieve the desired entry point pH was estimated for all the corrosive supplies using chemical equilibrium modeling (Table 5). Aeration would need to strip 60-70% of the carbon dioxide to reach pH of 7.4. Efficient aeration processes such as packed towers often require breaking head and repumping making aeration less cost-effective compared caustic soda based on capitol costs. However, the major advantage of aeration is the lack of chemicals and potentially lower lifecycle O&M costs. There is also less flexibility to meet different pH endpoints with an aeration system as it cannot be easily adjusted. Furthermore, it may not be possible to actually reach the “upper limits” using an aeration approach. This would need to be confirmed through piloting and/or additional modeling, communication with vendors, etc.

Adding orthophosphate would not be an option unless implemented system-wide which would mean also treating the sources that are not considered corrosive to lead or copper. Furthermore, orthophosphates are most effective in the pH range 7.2-7.8, so pH adjustment would be required anyway. Therefore, orthophosphate treatment was not considered cost effective or advisable for the City.

Because the wells have adequate alkalinity, use of soda ash or potash are not needed, but could be used in lieu of caustic soda. Soda ash dose and performance were evaluated and the estimated doses for cost planning purposes are also included in the Table 5. Soda ash doses are higher than the caustic doses due to the increases in alkalinity. Soda ash would likely be brought to site in powder format.

Page 19

Table 5. Summary of Modeled Treatment Options for the City’s Sources

1As 100% NaOH or Soda Ash 2Expected capacity after replacement 3Upper pH limit to avoid calcium carbonate precipitation

Pumping

Rate

Dose to

reach pH

7.4

Dose to

reach

upper pH

limit

Upper pH

limit3

Dose to

reach pH

7.4

Dose to

reach

upper pH

limit

Upper pH

limit3

CO2

removed

to reach

pH 7.4

CO2

removed

to reach

pH 7.4

CO2

remaining

at 7.4

CO2

removed to

reach Upper

limit

CO2

remaining

at Upper

limit

Upper pH

limit3

# Name gpm s.u. s.u. mg/L % mg/L % mg/L s.u.

S04 Well 4 7502

(additional)5 7.9 -- -- -- -- -- -- -- -- --

Madrona Well 1 1460

Madrona Well 2 1600

S28 Madrona Well 3 1600 7 11 7.9 17 27 7.8 8 57 6.1 90 1.6 7.9

S01 Well 1 300/6652 29 34 7.8 70 84 7.7 35 84 6.6 n/a n/a n/a

Well 2 600

Well 3 230

Beachcrest Well 1 180

Beachcrest Well 2 170

S27 Evergreen Estates 700 7 11 7.9 16 27 7.8 8 58 5.8 91.2 1.4 8.0

S20 McAllister 580 9 13 7.8 21 31 7.8 11 64 6 89.8 1.8 8.0

S06 Well 6C; Judd Hill 400 13 18 7.8 32 44 7.7 16 70 6.9 92.5 2.0 7.9

S29 Betti Well 1000 -- -- 7.3 -- -- -- -- -- -- 37.0 14.4 7.3

34S17 12 14 7.5 28 7.5 14 60 9.2 76.3

7.2 90.0 2.6 7.9

7.65.6

7.9

S18 14 18 7.7 34 44 7.7 17

7.8 10 63 5.8 88.9 1.9

70

mg/L1 mg/L1

S23 8 12 7.9 19 29

Caustic Soda Soda Ash Aeration

Sources

Page 20

5.6. Additional Water Quality Considerations

Increasing the system pH may increase the formation of trihalomethanes (THMs), although the groundwater is typically low in organic carbon and results from the City’s 2017 Water Quality Report indicate that the maximum result obtained was 10 ppb. Therefore, the proposed increase in pH is not anticipated to result in a regulatory concern due to increased THM formation.

Increasing the pH in range of 7.4-7.6 improves chemical stability of legacy iron and manganese in the distribution and provides an environment of lower metal solubility in general. In addition, pipe scales are more stable with smaller swings in the pH and more stable water quality conditions in the distribution.

The City receives occasional inquiries regarding very hard to remove scales on fixtures, shower stalls, etc. Since these deposits cannot be removed with acidic products, it is very likely that they are silica-based deposits. Several of the City’s wells have silica levels that could be considered problematic in terms of causing evaporative spotting and accumulation. Raising the pH will not impact the behavior of silica in the City’s distribution system, unless the pH is raised to > 9.5, the point at which silica precipitation can begin to occur.

Should the City increase chlorine levels to reduce iron release from pipes or for other reasons, a resultant increase in ORP will occur, which can be beneficial especially for lead control. Under highly oxidizing conditions, Pb(IV) scales may form which are very stable and less soluble than the Pb(II) carbonate-based scales, which are presumed to dominate under current pH, ORP, and DIC conditions.

6. Summary of Findings and Recommendations

1) Lead solubility is in good control in the City’s system, and is nearly optimized, as demonstrated by compliance monitoring results. However, some minor additional benefit could be realized by raising the pH to ≥ 7.0 in areas with Tier 1 homes, likely allowing the City to meet the b(3) criteria definition of optimization, and assisting with compliance with a future, more stringent LT-LCR.

2) The City meets the copper action level and is optimized for copper under the existing LCR. Copper solubility is in good control for aged surfaces dominated by malachite or tenorite.

3) Several of the City’s sources have water quality that is considered corrosive to new copper surfaces. The sources with combined higher DIC and low pH are the most corrosive to new copper surfaces, and could require treatment under the LT-LCR.

4) Given the complexity of the City’s system and significant blending between sources, pH ≥ 7.4 should be targeted for sources with existing treatment, those selected for future treatment, and any new wells that are brought on line in the future.

5) For the water quality characteristics of the City’s supply portfolio: a) Optimal corrosion control treatment for the existing LCR is achieved at pH ≥ 7.0. b) Optimal corrosion control treatment for the potential LT-LCR is achieved at pH ≥ 7.2 for

new copper surfaces. This should be revisited based on the final, published LT-LCR. c) Treatment of selected sources to pH ≥ 7.4 will help maintain these water quality goals

throughout the vast majority of the distribution system, under the existing and future LT-LCR.

6) It is not feasible or necessary to treat all the sources in the City’s system considering that not all of them are of significant capacity or supplying homes that are at risk of copper or lead corrosion.

Page 21

7) The risk assessment, source capacity, blending analysis, and potential impacts to overall distribution system water quality led to the following recommendations which will increase the pH to ≥ 7.4 in more than 84% of the City’s pumped capacity entering the distribution system.

a) Increase the caustic feed to raise the pH at Well 4 to 7.6. b) Install pH adjustment treatment to increase the entry point pH to 7.4-7.6 at the

following sources: i. S23 and S28

ii. S17 in conjunction with replacement of one of the Beachcrest wells that will also increase the source’s capacity.

iii. S18 in conjunction with replacing Well 1 (S1). iv. S27 as the major winter supply source.

8) After treatment is installed, evaluate remaining areas of higher risk for lead and copper corrosion separately as summarized in Appendix B – Action Plan. The Action Plan should be used to help the City determine when the system has reached optimal corrosion control. The Action Plan is based primarily on the existing LCR, but should nonetheless be beneficial towards compliance with a future, more stringent LT-LCR. However, action triggers may need to be modified depending on final LT-LCR revisions.

Page 22

References

AWWA, 2017, Internal Corrosion Control in Water Distribution Systems, Manual of Water Supply Practices M58, 2nd edition.

AWWA Webinar: Lead and Copper Corrosion 101: Principles and Guidance, January 17, 2018, Darren Lytle and Michael Schock, USEPA

Roth. D.R, Cornwell, D.A., Brown, R.A. and Via, S.H,. 2016, Copper Corrosion Under the Lead and Copper Tule Long-Term Revisions. Journal AWWA, 108:4 April.

Schock, M.R and Lytle, D.A. 2011. “Internal Corrosion and Deposition Control”. Water Quality and Treatment: A Handbook of Drinking Water, 6th ed., New York: McGraw-Hill

USEPA, 2016. Optimal Corrosion Control Treatment Evaluation Technical Recommendations for Primacy

Agencies and Public Water Systems. EPA 816-B-16-003. March 2016.

Page 23

Appendix A – Blending Analysis

Appendix B – Action Plan

Appendix C - Planning Level Cost Estimates for Caustic Soda pH Adjustment Facilities (RH2 Engineering)

1

APPENDIX A - BLENDING ANALYSIS

Blending analyses were completed for the areas that will receive water from sources that were not prioritized for treatment. This includes S06 – Judd Hill, S20 - McAllister, and S24/25 - Nisqually. The goal of the analyses was to evaluate the expected water pH in the distribution system within the zone of influence of these sources after blending with treated sources.

S06 Judd Hill Area

S06, Judd Hill, is a relatively small source. Its total contribution to the City’s supply portfolio was 3-4% in 2016-2017 and increased use is not planned. S06 will blend to some degree with water from S07 (Well 7) and S18 (wellfield for Wells 2 and 3) in the distribution system. Results of the analysis are shown in Figure 1. Assuming treated sources are treated to pH 7.4, pH 7.0 (Bin 2) can be reached once the blend fraction decreases below 75% Judd Hill water (e.g., at least 25% Well 7/S18 water). pH 7.2 (Bin 3) can be reached only when 25% of the blend is Judd Hill water and at least 75% of the water in the distribution system is from Well 7 or treated S18. Increasing the S18 entry point pH to 7.6 will reduce the amount of S18 water needed to reach pH 7.2 (Bin 3) down to 50%.

Figure 1. Expected pH at different blending levels near Source 6 (Judd Hill).

Nisqually (S24/24), 188 Zone

The 188 zone is supplied by Sources 24 and 25 and can receive some water from the 400 zone through

the Nisqually PRV. According to the City, Madrona and Betti wells would be the main sources supplying

this PRV and consequently, the 188 zone, when the PRV is operational. The blending analysis was

completed with the larger of the Nisqually sources, S25 (the Nisqually wells have very similar water

quality). Figure 2 shows the modeled pH in the distribution system when blending S25 with Betti or

treated Madrona water. To provide a minimum pH of 7.2, no more than 40% Nisqually water can be in

the blend (need at least 60% treated Madrona water at pH 7.4). However, Nisqually is a non-expanding

portion of the system, and new copper plumbing is not anticipated in this region. There are a few homes

that meet Tier 1 construction dates, so lead solder may be present. Thus, the target of the blending

analysis is to meet a minimum pH of 7.0. This can be met if the water in the distribution system has at

least 25% of the other supplies, that is, no more than 75% Nisqually water.

2

Increasing the treatment at Madrona to a higher entry point pH would lower the needed blending level

to meet the various pH targets. The average pH of Betti well is 7.15 and therefore, blended water pH

would not go above pH 7.2 to meet Bin 3, but will meet Bin 2 (pH ≥ 7).

Figure 2. Expected pH at different blending levels in the 188 Zone around Source 25 (Nisqually 19C).

McAllister (S20) and Evergreen Estates (S27), 337 Zone

Both McAllister (S20) and Evergreen Estates (S27) have been significant supplies for the City representing 10% and 16% of the total volume pumped in 2016 and 2017, respectively. S27 is also a priority well to meet winter demand. These sources typically serve the south 400-pressure zone where there are no Tier 1 homes and the southwest portion of the 337 zone (through PRVs).

Both of these areas have experienced growth and are still growing making them at higher risk for copper corrosion. All new development is using PEX-piping, but there is a large development with copper piping (no lead) near S27. To address this, the City is planning to install treatment at S27, after the other priority treatments have been completed. S27 was prioritized for treatment over S20 because of its larger water right and the plan is to blend S20 with treated S27 when the S20 is in use. As shown in Figure 3, the blending analyses indicates that if Evergreen is treated to pH 7.6, 50% blending level would be needed to maintain a minimum pH of 7.2 (Bin 3). To meet the Bin 2 criteria (maintain pH ≥ 7.0), the proportion of S20 in the overall supply can increase to greater than 90%.

3

Figure 3. Expected pH at different blending levels for McAllister (S20) with treated Evergreen Estates (S27)

Figure 4 shows the modeled distribution water pH when McAllister (S20) mixes with treated Madrona water. Having more than 40% of S20 supply will drop the distribution water pH below 7.2 (Bin 3), unless Madrona is treated to a minimum pH of 7.6. In this case, up to 50% S20 water can be in the blend while meeting Bin 3 criteria (maintain pH ≥ 7.2). To meet the Bin 2 criteria (maintain pH ≥ 7.0), the proportion of S20 in the overall supply can increase to greater than 90%.

Figure 4. Expected pH at different blending levels for McAllister (S20) and treated Madrona (S23/28)

The SW 337 zone has several Tier 1 homes. In the distribution system, the water from S20 and S27 may blend with each other, Madrona, or, if the PRV(s) are open to the 337 Zone, the sources supplying the Steilacoom and Union Mill reservoirs. The sources that feed these major reservoirs in the 337 zone include Sources 4, 7, 18, 9, and 10. Source 6 is not large enough in capacity to reach the reservoirs.

4

To estimate the water quality in the Steilacoom and Union Mill reservoirs, a hypothetical blend of the sources supplying that reservoirs was created. The blended portions of the sources were based on average volume pumped from each source in 2016 and 2017. This was considered to be more representative of the stored water than using the individual pumping capacities of the wells. Table 1 presents the blended water quality and the proportion of each source used to create the blend. Adding treatment to S18 has a significant overall impact on the pH of the reservoir water in the 400 zone. The increased treatment at S04 slightly increased the blended water pH in the reservoir, but did not change the overall blended water characteristics. Increasing the pH of S27 to a minimum of 7.4 will be compatible with the anticipated chemistry in the blending zones.

Table 1. Estimated water quality in Steilacoom and Union Mill Reservoirs based on supply blending

Source # S04 S07 S09 S10 S18

Proportion of the blend1 11.3% 32.1% 3.0% 27.2% 26.4%

Pump capacity (gpm) 750 1,800 650 1,000 830

Water Quality / Treatment Condition

TDS mg/L

pH s.u.

Alkalinity mg/L as CaCO3

Ca mg/L

DIC mg/L as C

Current Reservoir Water

94

7.21 75

49 21.0 Reservoir Water after S18 Treated to pH 7.4

7.43 80

Reservoir Water after S04 Treated to pH 7.6 and S18 Treated to pH 7.4

7.45 80

1 based on total gallons of water pumped from these sources in 2016 and 2017.

However, since treatment installation at S27 could take several years, Figure 5 was created to show impacts of untreated Evergreen Estates (S27) water blending with treated Madrona water and also with Steilacoom Reservoir water within the 337 zone. Greater than 90% untreated S27 water can be accommodated in the blend while still maintaining pH ≥ 7.0 (Bin 2).

Figure 5. Expected pH at different blending levels of S27 and Other 337 Zone Blended Supplies.

1

APPENDIX B - ACTION PLAN STEPS TO REACH OCCT

Due to the complexity of the City’s water system with multiple sources, treatments, water quality characteristics of supplies, and vintage of the homes, there is no simple solution for system-wide optimal corrosion control. The approach laid out in the corrosion control optimization report prioritized treatment installations to the largest, most corrosive sources that will have the most significant impact in the overall system. Additionally, the treatment locations were prioritized to target location of Tier 1 homes receiving water from untreated sources with corrosive water quality. To confirm and evaluate the level of optimization in the City’s water system, the following steps are proposed:

1) Conduct WQP monitoring to determine baseline conditions throughout the system, especially in

areas of highest concern including:

a) Quarterly monitoring for pH, temperature, alkalinity, and conductivity (for source tracing)

b) Add locations in the blending zones receiving water from untreated, potentially corrosive,

sources

i) Nisqually – due to potential Tier 1 homes, but non-expanding so no new copper

ii) Judd Hill – Adequate blending during summer when metals release is highest, but potential

hot spot during winter conditions, some Tier 1 era homes

iii) S20 service area – Blending zone with Madrona

iv) S27 service area – Blending zone with Madrona and Union Mills reservoir (337 zone blended

water). S27 to be treated but new WQP site needed to establish baseline conditions.

2) Treatment installation for the sources to increase entry point pH to a minimum of 7.4

a) 400 Zone

i) Install CCT at S23/28 (will also impact 337 zone)

ii) Install CCT at S17

iii) Install CCT at S27 (will also impact 337 zone)

b) 337 Zone

i) Increase caustic dose at S04

ii) Install CCT at S18 and S01-replacement

With these installations, at least 84% of the available source pumping capacity will be either noncorrosive or treated for corrosion control. Additional capacity will likely be available with the redevelopment of S17 and S01.

3) After treatment installation at S17, S23/28, and S18, WQP monitoring to determine the need for

increasing EP targets or modified well operational strategies for achieving the goal of at least pH 7.0

in the DS blending zones, and confirm the need for construction/installation of treatment at S27.

a) pH, alkalinity, and conductivity

b) Biweekly monitoring at entry points

c) Monthly monitoring at the current 12 WQP sites and the additional sites selected for targeting

the areas summarized in item 1b) above.

2

4) After the treatment systems at S17, S23/28, and S18 have been operational and meeting EP targets

for at least 4-6 months, conduct 2 consecutive 6-month rounds of LCR tap monitoring in accordance

with the LCR requirements (prioritizing Tier 1 homes).

5) Evaluate Results using Flow Chart below (to be re-evaluated according to requirements of the

revised LT-LCR).

6) If results indicate optimized corrosion control, provide results and recommendations for optimal

water quality parameter set points for each entry point and within the distribution system (by

pressure zone if appropriate) to the Department of Health.

3

Yes No

90th percentile of LCR Tap Samples

Pb ≤ 0.005 mg/L Cu ≤ 1.30 mg/L

Pb 0.006-0.015 mg/L Cu ≤ 1.30 mg/L

AL exceeded

b(3) Criteria Met, System Optimized

Identify what

changed

WQPs within optimal range?

Identify Risk Areas

System Optimized Increase Treatment Levels if Possible

Complete Investigative Tap Sampling Following DOH’s Hot Spot Approach. If the

issue is Copper, then prioritize on new construction

Evaluate Alternative Operational Strategies to Increase the Proportion of Non-Corrosive or

Treated Sources to the Area

Pb ≤ 0.015 mg/L Cu ≤ 1.30 mg/L

System Optimized Pb/Cu ≥ AL

Install Treatment to the source(s) supplying the

area

7/13/2018 11:07 AM J:\DATA\CEG\118-017\TECH MEMO\RH2 TECH MEMO RE COST FOR PH ADJUSTMENT FACILITIES.DOCX

TECHNICAL

MEMORANDUM

Client: Confluence Engineering Group/City of Lacey

Project: Water Quality Consultant

Project File: CEG 118.017.01.101 Project Manager: Dan Mahlum, PE

Composed by: Barney Santiago, PE

Reviewed by: Dan Mahlum, PE and Rick Ballard, PE

Subject: Well Nos. 1, 2, and 3, Well No. 4, and Madrona Wells pH Adjustment Facilities

Date: July 13, 2018

BACKGROUND Washington State Department of Health (DOH) has required the City of Lacey (City) to

update its 2014 corrosion control study and identify additional treatment to optimize

corrosion control. The City retained Confluence Engineering Group (Confluence) to

evaluate current source and distribution water quality and recommend treatment that

focuses on pH adjustment at the City’s sources. The City will use this information to

update its 2014 corrosion control study for DOH approval.

Confluence determined that the preferred locations for implementing additional pH

adjustment would be the Well Nos. 1, 2, and 3 site (DOH Source # S01 and S18), Well

No. 4 (S04), and the Madrona Well Nos. 1, 2, and 3 site (S23 and S28). Confluence

recommended caustic soda doses for these sources and retained RH2 Engineering, Inc.,

(RH2) to assist with estimating costs of the new pH adjustment facilities. This technical

memorandum summarizes the expected chemical usage, sizes chemical feed and storage

equipment, and presents conceptual construction and project cost estimates for the

proposed facilities. Well No. 4 currently has a pH adjustment system; this evaluation will

include operational changes to accommodate higher caustic soda doses at this site.

Signed: 07/13/2018 Signed: 07/13/2018

Melinda Friedman

Typewritten Text

Appendix C

Technical Memorandum RE: Well Nos. 1, 2, and 3, Well No. 4, and Madrona Wells pH Adjustment Facilities July 13, 2018

Page 2


WELL NO. 4 Well No. 4 currently has an existing pH adjustment facility that includes three

1,000-gallon storage tanks for 25-percent caustic soda and two metering pumps for

injection. Confluence determined that an increase in caustic soda dose is required to meet

the short-term target pH of 7.6. Confluence also provided an upper limit caustic soda

dose for future planning. These doses, along with source flows, maximum daily hourly

operation, and metering pump and chemical usage calculations are shown in Table 1.

Maximum daily hourly operation was estimated from the City’s 2017 12-month water

detail reports.

Table 1: Well No. 4 Caustic Soda Boost Calculations

Notes: Treatment quantities will be revisited once a new well is drilled and water quality and

pumping capacity is updated for the expanded site.

gpm = gallons per minute

NaOH = sodium hydroxide or caustic soda

MDD = maximum daily demand

mg/L = milligrams per liter

The short-term caustic dose boost would require an additional 0.28 gallons-per-hour

(gph) increase in existing metering pump speed to meet the target pH of 7.6. An

additional 135 gallons of 25-percent caustic soda will be consumed per month. To boost

Source NameDOH Source No.

Parameter Year 2018 Units

Average Flow Rate 750 gpm

Max Daily Operation 16 hours/day

Caustic Dose Boost to pH 7.6 (100% NaOH) 2.0 mg/L

Daily Caustic Feed (100% NaOH) 12 pounds/day

Daily Caustic Feed (25% NaOH Solution) 4 gallons/day

Additional Metering Pump Feed Rate 0.28 gal/hr

Estimated Additional Weekly Usage 31 gallons

Estimated Additional Monthly Usage 135 gallons

Parameter Year 2018 Units

Average Flow Rate 750 gpm

Max Daily Operation 16 hours/day

Caustic Dose to Upper Limit (100% NaOH) 4.6 mg/L

Daily Caustic Feed (100% NaOH) 28 pounds/day

Daily Caustic Feed (25% NaOH Solution) 10 gallons/day

Additional Metering Pump Feed Rate 0.65 gal/hr

Estimated Additional Weekly Usage 72 gallons

Estimated Additional Monthly Usage 310 gallons

Well No. 4S04

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pH

7.6


Page 3


pH to the upper limit (pH 7.9), the existing metering pumps would increase by 0.65 gph,

resulting in an additional 310 gallons consumed per month.

The City should be able to accommodate higher doses at Well No. 4 with minor

operational modifications. The City currently operates the existing 27 gph metering

pumps at approximately half stroke and half speed; therefore, the City has additional

metering pump capacity to accommodate higher doses. Regarding chemical usage, the

City purchased an average of 1,500 gallons of caustic soda from April through August in

2017. Chemical deliveries ranged from 1,256 to 1,836 gallons. Monthly delivery

frequency could remain the same but the City would need to order additional chemical to

accommodate higher caustic soda doses.

WELL NOS. 1, 2, AND 3 Confluence reviewed source water quality for Well Nos. 1, 2, and 3 (S01 and S18) and

provided caustic soda doses to meet the short-term target pH of 7.4 and an upper limit

dose if additional treatment is needed in the future. These doses, along with source flows,

maximum daily hourly operation, and metering pump and chemical usage calculations

are shown in Table 2. Maximum daily hourly operation was estimated from the City’s

2017 12-month water detail reports.


Page 4


Table 2: Well Nos. 1, 2, and 3 Caustic Soda Feed Calculations

Notes: DOH Sources S02 and S03 comprise the wellfield assigned as S18.





Chemical Feed Equipment Sizing

As shown in Table 2, the City will need metering pumps at the Well Nos. 1, 2, and 3 site

that have a capacity range from 0.54 to 6.69 gph. This will allow the City the flexibility

to boost pH at a variety of doses for the short-term and in the future regardless of which

well or combination of wells are operating at this site.

Regarding chemical storage, it is most cost-effective to size the total chemical tank

volume large enough to accept at least one full tanker truck delivery to prevent delivery

surcharges of partial deliveries. Tanker trucks have a capacity of 47,000 pounds of

chemical, or about 4,420 gallons of 25-percent caustic soda. RH2 recommends the total

storage volume to be 1.5 times the tanker truck capacity, or at least 6,630 gallons, to

provide the City with operational flexibility. This storage volume would require full

tanker deliveries every 3 months in the short term and about every 4 weeks in the future

at the higher caustic soda dose.

Source Name Well No. 1 Well No. 2 Well No. 3 Well No. 1 Well No. 2 Well No. 3DOH Source No. S01 S02 S03 S01 S02 S03

Parameter Units

Average Flow Rate 0 500 206 665 500 206 gpmMax Daily Operation 24 24 24 24 24 24 hours/day

Caustic Dose to pH 7.4 (100% NaOH) 29 14 14 29 14 14 mg/L

Daily Caustic Feed (100% NaOH) 0 84 35 232 84 35 pounds/day

Daily Caustic Feed (25% NaOH Solution) 0 31 13 87 31 13 gallons/dayMetering Pump Feed Rate 0.00 1.31 0.54 3.61 1.31 0.54 gallons/hr

Combined Metering Pump Feed Rate gallons/hr

Weekly Usage 0 220 91 607 220 91 gallons

Estimated Total Weekly Usage gallons

Estimated Monthly Usage 0 944 389 2,602 944 389 gallonsEstimated Total Monthly Usage gallons

Estimated Full Tanker Delivery Frequency weeks

Parameter Units

Average Flow Rate 0 500 206 665 500 206 gpmMax Daily Operation 24 24 24 24 24 24 hours/day

Caustic Dose to Upper Limit (100% NaOH) 34.4 18.2 18.2 34.4 18.2 18.2 mg/L






Estimated Monthly Usage 0 1,228 506 3,087 1,228 506 gallonsEstimated Total Monthly Usage gallons


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4,820

10.9 3.9

2.41 6.69

405 1,125

1,734

1.85 5.47

Year 2018 Year 2022 / 2028 MDD

918

Year 2018

311

1,334

14.2

3,936

4.8

Year 2022 / 2028 MDD


Page 5


Facility Cost Estimate

The engineer’s estimate of probable construction costs is $1.02 million, and the total

project cost is estimated at $1.515 million. A breakdown of costs is provided in Table 3.

Table 3: Well Nos. 1, 2, and 3 pH Adjustment Facility Cost Estimate

The proposed Well Nos. 1, 2, and 3 pH adjustment facility is conceptualized as a concrete

masonry unit (CMU) block structure covered by a wood truss roof with metal decking.

The building is sized at approximately 840 square feet with a total of three rooms,

consisting of a mechanical room, electrical room, and restroom. This structure will be

located above a below-grade, cast-in-place concrete secondary containment sump for

chemical spills. The chemical storage tanks will be elevated on concrete pads surrounded

by fiberglass-reinforced plastic grating.

The facility will be located within the site’s fence line near the existing access road to

minimize site improvements. A short access road will be paved to the building for

chemical tanker truck deliveries. Site utilities will consist of chemical injection piping,

water quality analyzer piping, and electrical and control system conduits. It is assumed

that a side sewer connection is available for floor drain wastes, and primary power and

water supply is available without major upgrades. It is assumed that no back-up power or

stormwater improvements are required.

Two 3,600-gallon chemical storage tanks will be in the mechanical room along with a

dual metering pump skid. Chemical piping from the metering pump skid will be routed to

a new static mixer installed in the combined well discharge header for injection. A water

quality analyzer will be added to monitor pH downstream of caustic injection. The

mechanical room also will include a fire sprinkler and alarm system, safety shower and

eyewash station, and a full heating, ventilation, and air conditioning (HVAC) system. The

restroom will include a toilet, sink, and hot water tank with thermostatic mixing valve.

Description Total Cost

1 Mobilization, Demobilization, Site Prep, and Cleanup $68,000

2 Site Work and Utilities $66,000

3 Facility Structural $266,000

4 Mechanical - pH Adjustment $209,000

5 Electrical and Controls $140,000

$749,000

$66,661

$815,661

$203,915

$1,020,000

$357,000

$137,700

$1,515,000

35% Indirect Costs

Total Estimated Project Cost

Construction Cost Subtotal

8.9% Sales Tax

Construction Cost with Tax

25% Construction Contingency

Total Estimated Construction Cost

10% Overall Project Contingency


Page 6


MADRONA WELL NOS. 1, 2, AND 3 Confluence reviewed source water quality for Madrona Well Nos. 1, 2, and 3 (S21 and

S22 that comprise the wellfield assigned as S23 and Well 3 is S28) and provided caustic

soda doses to meet the short-term target pH of 7.4 and an upper limit dose if higher

dosages are needed in the future. These doses, along with source flows, maximum daily

hourly operation, and metering pump and chemical usage calculations are shown in

Table 4. Maximum daily hourly operation was estimated from the City’s 2017 12-month

water detail reports.

Table 4: Madrona Well Nos. 1, 2, and 3 Caustic Soda Feed Calculations

Notes: DOH Sources S21 and S22 comprise the wellfield assigned as S28.





Chemical Feed Equipment Sizing

As shown in Table 4, the City will need metering pumps at the Madrona Well Nos. 1, 2,

and 3 site that have a capacity range from 2.10 to 10.19 gph. This will allow the City the

flexibility to boost the pH at a variety of doses for the short-term and in the future

regardless of which well or combination of wells are operating at this site.

Source Name Madrona 1 Madrona 2 Madrona 3 Madrona 1 Madrona 2 Madrona 3DOH Source No. S21 S22 S28 S21 S22 S28

Parameter Units

Average Flow Rate 1,460 1,600 1,600 1,600 1,600 1,600 gpmMax Daily Operation 13 19 8 13 19 8 hours/day

Caustic Dose to pH 7.4 (100% NaOH) 8.0 8.0 7.0 8.0 8.0 7.0 mg/L






Estimated Monthly Usage 854 1,367 504 935 1,367 504 gallonsEstimated Total Monthly Usage gallons


Parameter Units

Average Flow Rate 1,460 1,600 1,600 1,600 1,600 1,600 gpmMax Daily Operation 13 19 8 13 19 8 hours/day

Caustic Dose to Upper Limit (100% NaOH) 11.6 11.6 10.8 11.6 11.6 10.8 mg/L






Estimated Monthly Usage 1,238 1,983 777 1,356 1,983 777 gallonsEstimated Total Monthly Usage gallons


2,806

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pH

7.4

Year 2018 Year 2022 / 2028 MDD

6.69 6.90

636 655

2,725

4,116

4.7 4.6

7.0 6.7

Year 2018 Year 2022 / 2028 MDD

9.89 10.19

933 960

3,997


Page 7


Chemical storage recommendations are the same as Well Nos. 1, 2, and 3. Total chemical

tank volume is preferred to be sized large enough to accept a full tanker truck delivery of

chemical to prevent delivery surcharges for partial deliveries. RH2 recommends a total

storage volume of at least 6,630 gallons at this site as well to provide the City with

operational flexibility. This storage volume would require full tanker truck deliveries

every 7 weeks in the short term and about every 4.5 weeks in the future at the higher

caustic soda dose.

Facility Cost Estimate

The engineer’s estimate of probable construction costs is $1.04 million, and the total

project cost is estimated at $1.545 million. A breakdown of costs is provided in Table 5.

Table 5: Madrona Well Nos. 1, 2, and 3 pH Adjustment Facility Cost Estimate

The proposed Madrona Well Nos. 1, 2, and 3 pH adjustment facility is conceptualized as

a CMU block structure covered by a wood truss roof with metal decking. The building is

sized at approximately 770 square feet with a total of two rooms, a mechanical room and

an electrical room. This structure will be located above a below-grade, cast-in-place

concrete secondary containment sump for chemical spills; the chemical storage tanks will

be elevated on concrete pads surrounded by fiberglass-reinforced plastic grating.

It is assumed that the facility will be located adjacent to the existing chlorination building

to use the existing access road and concrete sidewalk. Minor site utilities will be required

such as chemical injection piping, water quality analyzer piping, and electrical and

control system conduits. Existing conduit and wiring may need to be rerouted around the

proposed building. It is assumed that primary power and water supply is available

without major upgrades, and the existing septic tank effluent pumping system can accept

minor floor drain wastes. It is assumed that no back-up power or stormwater

improvements are required.

Description Total Cost

1 Mobilization, Demobilization, Site Prep, and Cleanup $70,000

2 Site Work and Utilities $63,000

3 Facility Structural $249,000

4 Mechanical - pH Adjustment $240,000

5 Electrical and Controls $140,000

$762,000

$67,818

$829,818

$207,455

$1,040,000

$364,000

$140,400

$1,545,000Total Estimated Project Cost

Construction Cost Subtotal

8.9% Sales Tax

Construction Cost with Tax

25% Construction Contingency

Total Estimated Construction Cost

35% Indirect Costs

10% Overall Project Contingency


Page 8


Two 3,600-gallon chemical storage tanks will be in the mechanical room along with two

dual metering pump skids to match the site’s two chlorination feed locations. Chemical

piping from one metering pump skid will be routed to a new static mixer installed within

the Madrona Well No. 3 (DOH Source 28) building for caustic soda injection. Chemical

piping from the second metering pump skid will be routed to a new static mixer installed

in the combined discharge header of Madrona Well Nos. 1 and 2 for injection. Two water

quality analyzers will be added to monitor pH downstream of caustic injection. The

mechanical room will also include a fire sprinkler and alarm system, safety shower and

eyewash station, hot water tank with thermostatic mixing valve, and a full HVAC system.

Appendix C. Source Entry Point Water Quality

1

Appendix C. Entry Point Water Quality Data, 2011-2018

Site Date Lead


pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)

Specific Conduct

ance (µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

S01 3/8/2011 6.43 68.0 72.0 8.5 42.0 96.1 192.5 0.67 0.63 8 8 0.13 0.02 46.0

S01 4/19/2011 6.69 70.8 69.2 9.6 43.0 95.9 192.0 0.69 0.64 6 8 <0.1 <0.01 46.0

S01 7/18/2011 <0.001 6.75 70.8 70.8 13.0 44.0 93.4 187.1 0.59 0.56 5 8 <0.1 <0.01 49.0

S01 10/3/2011 6.58 70.4 73.2 13.2 56.0 101.6 203.0 0.59 0.58 7 8 53.0

S01 5/28/2009 <0.002 <0.02 72.0 5 9 <0.1 <0.01

S01 5/13/2015 <0.1

S01 12/14/2016 <0.001

OFFLINE 7/26/2017

S01 10/23/2017 0.001 <0.02 6.71 77.0 79.0 12.2 0.26 0.24 6 9 0.69 <0.01

OFFLINE 1/29/2018

OFFLINE 4/11/2018

S01 avg 0.001 <0.02 6.63 71.4 72.7 11.3 46.3 96.8 193.7 0.6 0.5 6.2 8.3 0.17 <0.01 48.5

S18 1/24/2011 6.70 78.0 76.0 8.8 51.0 99.5 199.5 0.72 0.63 6 7 <0.1 <0.01 39.0

S18 4/19/2011 6.92 81.2 76.4 9.5 52.0 99.9 199.0 0.70 0.64 6 7 <0.1 <0.01 43.0

S18 7/18/2011 <0.001 6.99 82.0 80.0 12.5 47.0 96.7 193.8 0.50 0.48 5 7 <0.1 <0.01 44.0

S18 10/3/2011 6.79 78.4 77.2 12.6 53.0 100.1 200.0 0.58 0.56 6 7 39.0

S18 5/27/2009 <0.002 <0.02 72.0 5 7 <0.1 <0.01

S18 5/13/2015 <0.1 <0.01

S18 12/14/2016 <0.001

S18 7/26/2017 <0.001 6.93 90.0 15.6 50.0 98.9 207.0 0.57 0.55 8 <0.05 <0.01

S18 10/23/2017 6.86 88.0 89.0 12.6 54.0 0.48 0.47 8

S18 1/29/2018 6.68 98.0 9.4 63.0 105.2 220.0 0.49 0.46 8 <0.05 <0.01

S18 4/11/2018 6.78 95.0 10.5 58.0 212.0 0.51 0.48 8

S18 avg 6.83 86.3 78.4 11.4 53.5 100.1 203.2 0.57 0.53 5.6 7.44 <0.1 <0.01 41.3

S04 1/24/2011 6.10 38.0 60.0 10.8 58.0 81.2 155.4 0.52 0.45 9 10 <0.1 <0.01 23.0

S04 4/18/2011 6.40 44.8 60.8 11.5 48.0 87.2 174.6 0.65 0.60 9 10 <0.1 <0.01 24.0

S04 7/18/2011 <0.001 6.44 58.0 64.0 12.8 49.0 86.3 172.5 0.61 0.59 9 10 <0.1 <0.01 26.0

S04 10/3/2011 6.36 41.2 60.0 11.9 52.0 87.4 174.9 0.50 0.49 8 10 25.0

S04 5/27/2009 <0.002 <0.02 56.0 10 10 <0.1 <0.01

S04 avg before CCT (pH adjustment) 6.33 45.5 60.2 11.8 51.8 85.5 169.4 0.57 0.53 9 10 <0.1 <0.01 24.5

S04 7/22/2013 7.50 82.0 56.0 12.5 213.0 0.59 0.60

S04 12/12/2016 <0.001

S04 7/24/2017 <0.001 7.26 66.0 13.5 44.0 99.7 208.0 0.60 0.54 11 <0.05 <0.01

S04 11/1/2017 <0.001 7.38 68.0 54.0 12.8 40.0 93.0 195.6 0.53 0.51 10

S04 1/29/2018 75.0 11.9 42.0 102.4 216.0 0.42 0.39 12 <0.05 <0.01

S04 4/11/2018 7.43 70.0 12.4 46.0 207.0 0.56 0.55 12

S04 avg after CCT (pH adjustment ) 7.39 72.2 55.0 12.6 43.0 98.4 207.9 0.54 0.52 11.3 <0.05 <0.01 24.5


2

Site Date Lead


pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)

Specific Conduct

ance (µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

S06 1/24/2011 6.95 76.0 81.0 8.8 43.0 92.2 181.2 0.66 0.53 7 12 <0.1 <0.01 43.0

S06 4/18/2011 6.89 73.6 82.8 9.5 54.0 101.6 203.0 0.24 0.19 5 13 <0.1 <0.01 45.0

S06 7/18/2011 <0.001 6.88 75.6 77.2 11.5 45.0 98.0 196.1 0.44 0.41 6 13 <0.1 0.01 44.0

S06 10/3/2011 6.90 68.4 67.6 14.1 48.0 92.6 185.4 0.63 0.60 7 9 <0.1 <0.01 44.0

S06 8/17/2009 <0.002 <0.02 82.0 6 12 <0.1 <0.01

S06 5/13/2015 <0.1 <0.01

S06 12/14/2016 <0.001

S06 7/26/2017 <0.001 6.75 77.0 13.5 44.0 89.9 186.9 0.71 0.28? 13 <0.05 <0.01

S06 10/23.2017 6.78 82.0 79.0 13.0 45.0 0.57 0.55 12

S06 1/29/2018 6.91 80.0 9.4 47.0 94.3 197.3 0.41 0.39 13 <0.05 <0.01

S06 4/11/2018 6.85 81.0 9.5 49.0 197.0 0.46 0.45 13

S06 avg 6.86 76.7 78.3 11.2 46.9 94.8 191.7 0.52 0.45 6.2 12.2 <0.1 <0.01 44.0

S07 1/26/2011 7.28 71.0 86.0 9.3 54.0 102.0 203.0 0.68 0.48 8 12 <0.1 <0.01 44.0

S07 4/19/2011 7.56 83.2 77.6 9.9 50.0 102.4 204.0 0.87 0.69 8 12 <0.1 <0.01 45.0

S07 7/18/2011 <0.001 7.47 80.0 11.2 49.0 103.0 207.0 0.90 0.76 8 13 <0.1 <0.01 53.0

S07 10/3/2011 7.41 80.8 80.8 11.5 61.0 102.1 204.0 0.64 0.53 7 12 47.0

S07 7/22/2010 <0.001 0.03 80.0 9 12 <0.1 <0.01

S07 5/13/2015 <0.1 <0.01

S07 12/29/2016 <0.001

S07 7/26/2017 <0.001 7.35 84.0 11.3 34.0 93.8 196.2 0.76 0.66 13 <0.05 <0.01

S07 10/23/2017 7.44 83.0 84.0 11.0 37.0 0.54 0.50 13

S07 1/29/2017 7.34 84.0 10.4 44.0 94.1 196.6 0.79 0.71 13 <0.05 <0.01

S07 4/11/2018 7.45 83.0 10.4 54.0 197.0 0.78 0.63 14

S07 avg <0.001 7.41 81.3 81.4 10.6 47.9 99.6 201.8 0.75 0.62 8.0 12.7 <0.1 <0.01 47.3

S09 1/24/2011 7.49 43.0 36.0 10.3 30.0 63.8 127.7 0.89 0.42 7 6 <0.1 0.02 47.0

S09 4/19/2011 7.72 48.8 40.8 9.9 27.0 75.0 150.0 1.35 0.82 10 8 <0.1 0.06 48.0

S09 7/18/2011 <0.001 7.78 42.8 30.4 11.2 18.0 58.2 116.6 1.61 1.03 7 5 <0.1 0.05 63.0

S09 10/3/2011 7.52 40.8 33.6 11.5 22.0 59.0 118.1 0.84 0.43 7 5 <0.1 0.03 59.0

S09 8/17/2009 <0.002 <0.02 49.0 6 8 0.11 0.08

S09 5/13/2015 <0.1 <0.01

S09 12/29/2016 <0.001

S09 7/26/2017 <0.001 7.59 43.0 11.2 21.0 50.5 106.9 0.50 6 0.1 0.07

S09 10/23/2017 7.72 42.0 39.0 11.1 23.0 0.70 0.68 5

S09 1/29/2018 7.54 43.0 10.5 25.0 55.5 116.8 1.21 0.69 5 0.08 0.06

S09 4/11/2018 7.69 43.0 10.5 28.0 113.0 1.27 0.71 6

S09 avg <0.001 7.63 43.3 38.1 10.8 24.3 60.3 122.7 1.10 0.66 7.4 6.0 0.07 0.05 54.3


3

Site Date Lead


pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)

Specific Conduct

ance (µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

S10 1/24/2011 7.42 53.0 61.0 9.6 45.0 81.2 162.7 0.64 0.54 7 11 <0.1 <0.01 29.0

S10 4/19/2011 7.58 62.8 61.6 9.8 43.0 85.1 170.3 0.56 0.49 7 10 <0.1 <0.01 30.0

S10 7/18/2011 <0.001 7.64 70.4 60.8 13.3 40.0 83.3 166.7 0.86 0.80 7 11 <0.1 <0.01 33.0

S10 10/3/2011 7.52 57.6 62.4 13.0 42.0 85.8 171.6 0.63 0.60 8 11 33.0

S10 5/13/2015 <0.1 <0.01

S10 8/17/2009 <0.002 <0.02 63.0 6 10 <0.1 <0.01

S10 12/29/2016 0.001

S10 7/26/2017 <0.001 7.49 66.0 11.6 44.0 81.5 170.3 0.66 0.58 13 <0.05 <0.1

S10 10/23/2017 7.42 68.0 75.0 11.0 49.0 0.52 0.50 13

S10 1/29/2018 7.31 67.0 10.7 51.0 84.8 177.2 0.30 0.27 13 <0.05 <0.01

S10 4/11/2018 7.60 67.0 11.1 66.0 176.0 0.54 0.52 13

S10 avg 7.50 64.0 64.0 11.3 47.5 83.6 169.8 0.59 0.54 7.0 11.7 <0.1 <0.01 31.3

S17 1/25/2011 6.86 103.0 113.0 10.7 84.0 132.1 0.62 0.52 11 10 <0.1 <0.01 29.0

S17 4/18/2011 6.99 98.8 107.6 11.3 88.0 134.2 268.0 0.67 0.55 10 10 0.16 0.03 33.0

S17 7/18/2011 <0.001 6.99 112.8 12.1 68.0 132.0 264.0 0.81 0.78 10 10 <0.1 <0.01 33.0

S17 10/4/2011 7.13 98.4 116.4 12.0 75.0 137.8 275.0 0.96 0.88 11 10 <0.1 <0.01 34.0

S17 5/13/2015 <0.1

S17 12/21/2010 <0.001 <0.02 111.0 10 10 <0.1 <0.01

S17 12/12/2016 <0.001

S17 7/26/2017 <0.001 6.92 97.0 4.8 63.0 118.0 246.0 0.63 0.62 11 <0.05 <0.01

S17 10/23/2017 7.08 93.0 104.0 12.9 71.0 0.70 0.68 10

S17 Offline for rehab

S17 avg <0.001 7.00 98.0 110.8 10.6 74.8 130.8 263.3 0.73 0.67 10.4 10.1 0.03 0.01 32.3

S19 1/25/2011 7.47 40.0 33.0 11.5 21.0 55.2 110.5 0.81 0.64 9 2 <0.1 <0.01 47.0

S19

S19 8/10/2011 <0.001 7.60 42.0 33.6 11.7 20.0 58.6 117.5 0.91 0.78 9 3 <0.1 <0.01 46.0

S19 10/4/2011 7.61 40.0 27.6 11.1 17.0 74.0 148.1 0.87 0.73 8 2 54.0

S19 5/13/2015 0.012

S19 12/12/2016 <0.001

S19 7/26/2017 <0.001 7.81 40.0 11.7 19.0 46.4 97.6 0.70 3 <0.05 <0.01

S19 10/23/2017 7.62 39.0 36.0 11.4 23.0 0.88 0.70 2

S19 1/30/2018 7.56 40.0 10.8 25.0 49.7 104.8 0.63 0.60 2 <0.05 <0.01

S19 4/25/2018 7.63 39.0 11.1 18.0 101.0 0.84 0.72 2

S19 avg <0.001 7.61 40.0 32.6 11.3 20.4 56.8 115.7 0.82 0.70 8.7 2.3 <0.1 0.01 49.0


4

Site Date Lead


pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)

Specific Conduct

ance (µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

S20 3/8/2011 6.78 66.0 83.0 11.3 42.0 99.5 199.2 0.59 0.56 8 8 <0.1 <0.01 39.0

S20 4/18/2011 7.04 72.0 74.8 10.7 54.0 101.0 201.0 0.59 0.55 8 8 <0.1 <0.01 42.0

S20 7/19/2011 <0.001 6.81 67.2 76.8 11.6 56.0 96.4 192.9 0.61 0.57 7 8 <0.1 <0.01 43.0

S20 10/4/2011 6.96 65.2 76.4 11.7 57.0 97.3 194.8 0.58 0.57 7 8 42.0

S20 5/28/2009 <0.002 <0.02 74.0 7 8 <0.1 <0.01

S20 12/12/2016 <0.001

S20 7/27/2017 <0.001 7.10 69.0 14.7 49.0 83.2 178.5 0.64 0.63 8 <0.05 <0.01

S20 10/25/2017 6.99 63.0 84.0 11.4 53.0 0.78 0.73 8

S20 1/30/2018 6.91 71.0 11.2 55.0 98.5 206 0.90 0.88 8 <0.05 <0.01

S20 4/12/2018 7.10 71.0 11.2 55.0 191 0.40 0.38 8

S20 avg 6.96 68.1 78.2 11.7 52.6 96.0 195.4 0.64 0.61 7.4 8.0 <0.1 <0.01 41.5

S23 1/26/2011 6.88 65.0 78.0 9.8 72.0 88.4 177.0 0.41 0.38 7 7 <0.1 <0.01 36.0

S23 4/18/2011 7.14 68.4 72.0 11.3 54.0 95.5 191.1 0.74 0.70 7 8 <0.1 <0.01 37.0

S23 7/19/2011 <0.001 6.87 65.2 72.8 14.5 47.0 93.1 186.0 0.56 0.52 7 8 <0.1 <0.01 41.0

S23 10/5/2011 7.08 63.6 71.2 13.9 44.0 91.8 183.7 0.55 0.54 7 7 40.0

S23 8/17/2009 0.002 <0.02 74.0 6 7 <0.1 <0.01

S23 12/12/2016 <0.001

S23 7/26/2017 <0.001 6.92 66.0 21.2 48.0 86.6 181.3 0.46 0.42 8 <0.05

S23 10/24/2017 7.04 66.0 80.0 14.5 50.0 0.30 0.29 8

S23 2/15/2018 7.08 65.0 10.3 38.0 86.9 181.8 0.20 0.12 8 <0.05 <0.01

S23 - offline

S23 avg 0.001 7.00 65.6 74.7 13.6 50.4 90.4 183.5 0.46 0.42 6.8 7.6 <0.1 <0.01 38.5

S24 1/25/2011 7.05 52.0 53.0 11.1 36.0 67.1 134.3 0.71 0.62 5 4 <0.1 <0.01 35.0

S24 4/18/2011 7.27 55.6 47.2 10.9 32.0 68.7 137.6 0.72 0.66 6 4 <0.1 <0.01 39.0

S24 7/19/2011 <0.001 7.04 56.8 50.4 11.9 37.0 69.2 138.6 0.73 0.71 6 4 <0.1 <0.01 41.0

S24 10/4/2011 7.14 52.8 52.0 11.6 41.0 68.9 137.9 0.73 0.70 6 4 40.0

S24 8/17/2009 <0.002 <0.02 53.0 5 4 <0.1 <0.01

S24 12/29/2016 <0.001

S24 7/26/2017 <0.001 7.23 57.0 12.0 32.0 60.1 128.3 0.60 0.51 4 <0.05 <0.01

S24 10/23/2017 6.97 55.0 51.0 12.0 36.0 0.68 0.66 4

S24 1/29/2018 7.01 77.0 11.1 34.0 62.0 130.1 0.39 0.38 4 <0.05 <0.01

S24 4/11/2018 7.14 56.0 11.1 36.0 130.0 0.34 0.29 4

S24 avg <0.001 7.11 57.8 51.1 11.5 35.5 66.0 134.5 0.61 0.57 5.6 4.0 <0.1 <0.01 38.8


5

Site Date Lead


pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)

Specific Conduct

ance (µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

S25 1/25/2011 6.80 53.0 53.0 11.1 33.0 67.9 135.7 0.69 0.58 6 4 <0.1 <0.01 37.0

S25 4/18/2011 6.98 61.6 48.0 10.8 44.0 70.6 141.2 0.63 0.56 6 3 <0.1 0.01 42.0

S25 7/19/2011 <0.001 6.76 58.0 49.6 11.5 34.0 70.3 140.6 0.60 0.53 6 3 <0.1 0.01 44.0

S25 10/4/2011 6.92 58.0 61.2 11.4 30.0 69.1 138.7 0.57 0.55 6 3 <0.1 0.01 44.0

S25 8/17/2009 <0.002 <0.02 51.0 5 3 <0.1 <0.01

S25 12/29/2016 <0.001

S25 7/26/2017 <0.001 6.94 64.0 12.8 35.0 69.6 145.9 0.66 0.64 4 <0.05 0.01

S25 10/23/2017 7.00 59.0 58.0 11.9 36.0 0.59 0.53 4

S25 1/29/2018 6.87 63.0 11.0 38.0 68.1 142.9 0.52 0.48 3 <0.05 <0.01

S25 4/11/2018 6.89 63.0 11.2 32.0 143.0 0.36 0.31 4

S25 avg <0.001 6.90 60.0 53.5 11.5 35.3 69.3 140.8 0.58 0.52 5.8 3.4 <0.1 <0.01 41.8

S27 1/25/2011 6.88 57.0 69.0 10.2 90.0 89.5 179.2 0.62 0.49 7 7 <0.1 <0.01 34.0

S27 4/18/2011 7.11 60.8 68.0 10.2 36.0 91.5 183.1 0.58 0.54 7 7 <0.1 <0.01 35.0

S27 7/19/2011 <0.001 6.83 58.8 69.2 11.7 47.0 88.8 177.7 0.59 0.57 6 7 <0.1 <0.01 38.0

S27 8/17/2009 <0.002 <0.02 69.0 6 7 <0.1 <0.01

S27 12/12/2016 <0.001

S27 7/26/2017 <0.001 7.10 61.0 14.7 44.0 83.2 178.5 0.64 0.63 7 <0.05 <0.01

S27 10/24/2017 7.01 60.0 77.0 12.4 48.0 0.53 0.49 7

S27 1/30/2018 6.88 61.0 10.4 48.0 84.8 177 0.58 0.56 7 <0.05 <0.01

S27 4/11/2018 7.06 62.0 11.2 49.0 171 0.61 0.58 8

S27 avg <0.001 6.98 60.1 70.4 11.5 51.7 87.6 179.1 0.59 0.55 6.5 7.1 <0.1 <0.01 35.7

S28 1/25/2011 6.88 61.0 78.0 10.2 52.0 92.4 184.8 0.47 0.37 7 7 <0.1 <0.01 35.0

S28 4/18/2011 7.15 67.6 72.4 10.9 47.0 97.4 194.9 0.56 0.51 7 7 <0.1 <0.01 37.0

S28 7/19/2011 <0.001 6.94 64.0 74.0 13.0 48.0 94.2 188.5 0.56 0.53 7 8 <0.1 <0.01 41.0

S28 10/5/2011 7.06 63.6 70.8 11.8 51.0 92.1 184.2 0.55 0.54 7 8 40.0

S28 7/21/2010 0.004 <0.02 76.0 7 7 <0.1 <0.01

S28 12/12/2016 <0.001

S28 7/27/2017 <0.001 7.00 68.0 17.6 48.0 88.7 185.3 0.56 0.51 8 <0.05 <0.01

S28 10/24/2017 7.05 65.0 79.0 14.1 53.0 0.23 0.20 8

S28 -offline

S28 -offline

S28 avg 0.002 7.01 64.9 75.0 12.9 49.8 93.0 187.5 0.49 0.44 7.0 7.6 <0.1 <0.01 38.3


6

Site Date Lead


pH Alkalinity

(mg/L CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)

Specific Conduct

ance (µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

S29 1/25/2011 7.09 147.0 170.0 8.9 153.0 185.3 0.70 0.62 24 10 <0.1 <0.01 34.0

S29 4/18/2011 7.15 150.0 154.0 10.3 121.0 181.4 362.0 0.81 0.68 23 10 <0.1 <0.01 35.0

S29 7/18/2011 <0.001 7.17 150.0 11.4 101.0 168.0 337.0 0.66 0.62 19 10 <0.1 <0.01 39.0

S29 10/4/2011 7.23 140.0 156.4 12.3 110.0 182.0 363.0 0.88 0.86 21 11 42.0

S29 8/27/2009 <0.002 0.04 158.0 23 9 <0.1 <0.01

S29 6/17/2016 <0.001 <0.1 <0.01

S29 12/12/2016 <0.001

S29 7/26/2017 <0.001 7.07 124.0 12.1 68.0 138.1 288.0 0.74 0.72 11 <0.05 <0.01

S29 10/23/2017 7.15 124.0 130.0 13.3 87.0 156.7 326.0 0.50 0.47 11

S29 1/30/2018 7.05 128.0 10.7 79.0 142.3 295.0 0.34 0.32 11 <0.05 <0.01

S29 4/11/2018 7.14 129.0 10.7 98.0 287.0 0.49 0.43 12

S29 avg <0.001 7.13 134.6 153.1 11.2 102.1 164.8 322.6 0.64 0.59 22 10.6 <0.1 <0.01 37.5

Appendix D. Distribution Tap Water Quality

1

Appendix D. Distribution Tap Water Quality Data

Site Date Lead

(mg/L) pH

Alkalinity (mg/L

CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)


(µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

SS07 1/27/2011 6.60 59 64 8.5 42 82.7 165.3 0.66 0.62 6 7 <0.1 <0.01 40

SS07 4/20/2011 6.89 60.0 55.6 10.1 32 76.2 152.6 0.63 0.60 6 5 <0.1 <0.01 39

SS07 7/21/2011 <0.001 6.75 64.4 70.8 16.2 22 93.1 186.3 0.54 0.50 7 8 <0.1 <0.01 34

SS07 10/6/2011 6.85 67.2 74.4 13.4 62 102.0 204.0 0.51 0.49 7 8 38

SS07 Avg 2011 6.8

SS07 6/13/2013 6.9 31.2 67.6 13.7 169.0

SS07 7/22/2013 7.1 61.6 68.8 16.1 165.0

SS07 4/23/2014 7.3 58.4 68.8 11.8 175.8

SS07 Avg 2013-2014 7.1

SS07 7/24/2017 6.98 62.0 14.4 26 81.7 171.1 0.61 0.60 7 <0.05 <0.01

SS07 9/11/2017 6.98 62.8 16.2 74.7 157.4 0.67 0.62

SS07 10/25/2017 <0.001 7.01 60.0 70.0 12.8 39 87.8 183.4 0.60 0.59 7

SS07 12/5/2017 7.06 60.4 9.6 103.6 216.0 0.63 0.60

SS07 1/30/2018 6.91 61.0 8.2 52 83.9 175.6 0.55 0.43 7 <0.05 <0.01

SS07 3/19/2018 7.19 67.6 9.1 165.0 0.59 0.53

SS07 4/9/2018 7.03 62.0 10.0 47 172.0 0.55 0.51 8

SS07 Avg 2017-2018 7.0 62.3 70.0 11.5 41.0 86.3 177.2 0.60 0.55 7.3 <00.5 <0.01 37.8

SS12 1/27/2011 6.78 61 73 9.6 54 93.8 187.8 0.52 0.49 7 7 <0.1 <0.01 36

SS12 4/20/2011 7.07 67.6 73.2 10.3 46 96.8 193.8 0.50 0.49 8 8 <0.1 <0.01 37

SS12 7/21/2011 <0.001 6.81 67.2 71.2 13.2 21 94.3 188.0 0.52 0.54 7 8 <0.1 <0.01 34

SS12 10/5/2011 7.08 64.4 71.2 12.8 46 113.0 226.0 0.54 0.52 7 8 39

SS12 Avg 2011 6.9

SS12 6/13/2013 6.6 32.4 72.4 13.3 169.0

SS12 7/22/2013 6.8 67.6 72.4 13.7 171.0 0.37 0.37

SS12 4/23/2014 7.1 63.2 75.2 12.1 183.1

SS12 Avg 2013-2014 6.8

SS12 7/24/2017 <0.001 7.03 68.0 14.6 48 85.6 179.3 0.55 0.47 8 <0.05 <0.01

SS12 9/11/2017 6.98 73.2 15.9 85.7 179.3 0.58 0.51

SS12 10/25/2017 <0.001 7.03 66.0 76.0 13.6 49 98.7 206.0 0.58 0.54 8

SS12 12/5/2017 7.07 60.8 13.0 82.1 172.0 0.60 0.57

SS12 1/31/2018 6.99 62.0 8.4 48 84.1 176.0 0.57 0.56 7 <0.05 <0.01

SS12 3/19/2018 7.14 68.8 9.5 178.0 0.57 0.51

SS12 4/9/2018 7.02 63.0 10.4 45 175.0 0.51 0.50 8

SS12 Avg 2017-2018 7.0 66.0 76.0 12.2 47.5 87.2 180.8 0.57 0.52 7.8 <0.05 <0.01 36.5

SS14 1/27/2011 6.68 59 68 9.0 52 90.4 180.4 0.52 0.45 8 6 <0.1 <0.01 37

SS14 4/20/2011 7.09 150.0 154.8 10.4 94 181.0 363 0.73 0.69 21 10 <0.1 <0.01 38

SS14 7/21/2011 <0.001 6.82 136.0 141.6 14.8 41 166.0 333 0.53 0.50 20 10 <0.1 <0.01 33

SS14 10/5/2011 7.22 52.0 51.2 15.3 32 85.8 171.8 0.53 0.52 7 5 45

SS14 Avg 2011 7.0


2

Site Date Lead

(mg/L) pH

Alkalinity (mg/L

CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)


(µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

SS14 6/13/2013 6.8 57.6 119.2 14.9 267.0

SS14 7/22/2013 7.2 80.4 79.2 15.6 186.0

SS14 4/23/2014 7.43 79.6 78.8 12.6 201.0

SS14 Avg 2013-2014 7.1

SS14 7/24/2017 <0.001 7.14 109.0 18.3 70 121.4 253.0 0.51 0.51 11 <0.05 <0.01

SS14 9/11/2017 7.40 98.8 14.0 97.5 203.0 0.64 0.38

SS14 10/25/2017 <0.001 7.28 82.0 83.0 12.6 42 136.3 283.0 0.59 0.58 13

SS14 12/5/2017 7.43 84.8 10.0 90.9 190.6 0.65 0.57

SS14 1/31/2018 7.31 83.0 9.3 58 95.1 199.0 0.73 0.59 13 <0.05 <0.01

SS14 3/19/2018 7.43 46.4 9.9 187.0 0.44 0.35

SS14 4/9/2018 7.43 84.0 10.5 58 197.0 0.67 0.60 13

SS14 Avg 2017-2018 7.3 84.0 83.0 12.1 57.0 108.2 216.1 0.60 0.51 12.5 <0.05 <0.01 38.3

SS17 1/27/2011 6.52 54 68 8.9 40 76.8 153.4 0.75 0.59 5 5 <0.1 <0.01 39

SS17 4/20/2011 7.29 78.8 77.2 10.0 39 98.5 197.1 0.63 0.57 8 11 <0.1 <0.01 43

SS17 7/21/2011 <0.001 6.81 75.2 76.0 15.2 20 98.0 196.0 0.70 0.61 8 10 <0.1 <0.01 38

SS17 10/6/2011 6.93 62.4 66.4 14.1 43 95.2 188.9 0.60 0.58 6 6 37

SS17 Avg 2011 6.9

SS17 6/13/2013 6.8 28.4 61.2 13.7 138.0

SS17 7/22/2013 6.9 64.4 63.6 16.1 152.0

SS17 4/23/2014 7.1 74.0 74.8 189.6

SS17 Avg 2013-2014 6.9

SS17 7/24/2017 6.98 70.0 16.5 52 88.5 185.3 0.53 0.51 8 <0.05 <0.01

SS17 9/11/2017 7.14 87.6 16.0 80.4 168.0 0.64 0.62

SS17 10/25/2017 <0.001 7.11 69.0 82.0 13.0 64 100.8 210.0 0.51 10

SS17 12/5/2017 7.32 83.6 9.1 94.9 198.5 0.56 0.52

SS17 1/30/2018 7.06 81.0 8.7 48 95.1 198.7 0.54 0.49 13 <0.05 <0.01

SS17 3/19/2018 7.40 82.0 9.0 189.0 0.63 0.36

SS17 4/9/2018 7.26 82.0 10.1 52 196.0 0.67 0.60 13

SS17 Avg 2017-2018 7.2 79.3 82.0 11.8 54.0 91.9 192.2 0.60 0.52 11.0 <0.05 <0.01 39.3

SS20 1/27/2011 6.94 68 80 7.7 61 102.0 205.0 0.42 0.37 12 6 <0.1 <0.01 41

SS20 4/20/2011 6.97 98.4 110.8 9.7 70 133.0 267 0.62 0.59 10 10 <0.1 <0.01 32

SS20 7/21/2011 <0.001 6.73 97.2 109.2 16.5 36 132.0 266 0.72 0.66 10 11 <0.1 <0.01 30

SS20 10/5/2011 7.72 42.0 30.4 15.2 18 64.3 127.7 0.46 0.45 8 2 49

SS20 Avg 2011 7.1

SS20 4/23/2014 7.0 97.6 110.0 10.6 251.0

SS20

SS20 7/24/2017 0.001 6.83 100.0 15.2 86 117.8 245.0 0.63 0.60 11 <0.05 <0.01

SS20 9/11/2017 6.88 104.4 15.0 116.9 244.0 0.62 0.60

SS20 10/25/2017 <0.001 7.67 48.0 42.0 14.0 28 71.6 150.2 0.42 0.42 3

SS20 12/5/2017 7.07 84.0 10.0 89.4 186.9 0.46 0.42

SS20 1/30/2018 7.25 45.0 8.2 31 56.9 119.4 0.49 0.45 3 <0.05 <0.01


3

Site Date Lead

(mg/L) pH

Alkalinity (mg/L

CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)


(µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

SS20 3/19/2018 7.28 60.0 8.6 139.0 0.40 0.37

SS20 4/9/2018 6.95 102.0 9.9 91 250.0 0.41 0.38 11

SS20 Avg 2017-2018 7.1 77.6 42.0 11.6 59.0 90.5 190.6 0.49 0.46 11.0 5.7 <0.05 <0.01 38.0

SS36 1/27/2011 7.20 42 43 8.5 39 65.0 131.0 0.66 0.56 10 3 <0.1 <0.01 46

SS36 4/20/2011 6.96 99.2 111.6 9.8 68 132.0 264 0.66 0.62 10 10 <0.1 <0.01 32

SS36 7/21/2011 <0.001 6.97 129.2 134.0 15.4 44 162.0 325 0.52 0.51 19 10 <0.1 <0.01 35

SS36 10/5/2011 7.66 42.8 32.4 14.6 16 75.5 153.9 0.52 0.52 8 2 50

SS36 Avg 2011 7.2

SS36 4/23/2014 7.7 42.0 34.0 12.1 139.4

SS36 7/24/2017 <0.001 7.36 57.0 16.7 29 65.6 137.8 0.72 0.62 4 <0.05 <0.01

SS36 9/11/2017 7.27 56.4 17.3 66.5 139.7 0.61 0.58

SS36 10/25/2017 <0.001 7.62 42.0 37.0 13.9 23 75.9 158.8 0.62 0.55 3

SS36 12/5/2017 7.65 42.4 10.3 50.1 105.5 0.67 0.62

SS36 1/30/2018 7.51 41.0 9.0 27 51.1 107.1 0.58 0.54 2 <0.05 <0.01

SS36 3/19/2018 7.70 42.8 9.3 104.0 0.65 0.60

SS36 4/9/2018 7.47 53.0 11.1 32 132.0 0.52 0.46 4

SS36 Avg 2017-2018 7.5 47.8 37.0 12.5 27.8 61.8 126.4 0.62 0.57 3.3 <0.05 <0.01 40.8

SS55 1/27/2011 6.70 50 51 9.0 42 68.8 138.7 0.49 0.43 6 4 <0.1 <0.01 40

SS55 4/20/2011 7.09 66.0 73.2 10.5 46 94.4 188.9 0.50 0.48 7 8 <0.1 <0.01 39

SS55 7/21/2011 <0.001 6.68 57.6 46.8 16.6 15 69.6 139.8 0.33 0.30 6 3 <0.1 <0.01 37

SS55 10/5/2011 7.04 56.0 47.6 14.8 32 88.3 177.4 0.44 0.42 6 3 41

SS55 Avg 2011 6.9

SS55 4/23/2014 7.2 60.4 53.2 11.8 143.7

SS55 7/24/2017 0.001 6.94 63.0 16.7 35 66.4 139.4 0.53 0.51 4 <0.05 <0.01

SS55 9/11/2017 6.92 64.8 15.3 64.8 135.9 0.63 0.61

SS55 10/25/2017 <0.001 7.00 58.0 52.0 12.0 33 73.3 153.6 0.60 0.58 4

SS55 12/5/2017 7.09 62.8 8.7 69.6 146.6 0.38 0.36

SS55 1/30/2018 6.86 60.0 9.1 39 67.0 140.6 0.40 0.39 4 <0.05 <0.01

SS55 3/19/2018 7.00 63.2 9.9 136.0 0.39 0.30

SS55 4/9/2018 7.09 62.0 10.9 38 139.0 0.35 0.33 4

SS55 Avg 2017-2018 7.0 62.0 52.0 11.8 36.3 68.2 141.6 0.47 0.44 4.0 <0.05 <0.01 39.3

SS90 1/27/2011 6.91 69 80 7.4 72 101.0 202.0 0.46 0.46 9 7 <0.1 <0.01 39

SS90 4/20/2011 6.99 94.8 106.0 9.8 58 124.0 248 0.55 0.52 12 8 <0.1 <0.01 38

SS90 7/21/2011 <0.001 6.95 144.0 142.0 14.4 52 167.0 333 0.55 0.52 20 11 <0.1 <0.01 34

SS90 10/5/2011 7.26 68.0 59.6 15.2 36 103.0 208.0 0.53 0.43 8 5 45

SS90 Avg 2011 7.0


4

Site Date Lead

(mg/L) pH

Alkalinity (mg/L

CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)


(µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

SS90 6/13/2013 7.0 64.4 136.4 15.2 297.0

SS90 7/22/2013 6.9 122.4 127.2 17.0 279.0

SS90 4/25/2014 7.2 71.2 68.8 12.0

SS90 Avg 2013-2014 7.0

SS90 7/24/2017 <0.001 7.08 119.0 18.2 108 132.8 280.0 0.67 0.63 11 <0.05 <0.01

SS90 9/11/2017 7.40 87.6 19.1 95.6 199.9 0.52 0.45

SS90 10/25/2017 <0.001 7.25 82.0 87.0 13.6 43 108.1 226.0 0.44 0.41 12

SS90 12/5/2017 7.43 85.2 9.3 94.9 198.3 0.55 0.51

SS90 1/31/2018 7.12 62.0 7.9 44 77.6 162.5 0.51 0.45 6 <0.05 <0.01

SS90 3/19/2008 7.46 90.8 8.3 188.0 0.59 0.30

SS90 4/9/2018 7.44 84.0 9.3 64 198.0 0.53 0.49 13

SS90 Avg 2017-2018 7.3 87.2 87.0 12.2 64.8 101.8 207.5 0.54 0.46 10.5 <0.05 <0.01 39.0

SS02 7/24/2017 0.002 7.35 84.0 20.6 40 96.8 201.0 0.43 0.33 13 0.05 <0.01

SS02 9/11/2017 7.40 87.6 21.2 95.8 200.0 0.73 0.67

SS02 10/25/2017 6.96 80.0 84.0 14.6 103.6 217.0 0.40 0.39

SS02 12/5/2017 7.33 89.6 10.4 95.3 199.4 0.59 0.45

SS02 1/31/2018 7.30 82.0 8.5 44 96.6 202.0 0.64 0.55 13 <0.05 <0.01

SS02 3/19/2018 7.42 75.6 9.6 188.0 0.61 0.50

SS02 4/9/2018 7.36 83.0 11.9 64 197.0 0.62 0.56 13

SS02 Avg 2017-2018 7.3 83.1 84.0 13.8 49.3 97.6 200.6 0.57 0.49 13.0 <0.04 <0.01 39.0

SS11 7/24/2017 <0.001 7.31 84.0 15.9 57 95.7 199.0 0.49 0.43 13 <0.05 <0.01

SS11 9/11/2017 6.81 91.2 14.9 99.2 206.0 0.54 0.51

SS11 10/25/2017 6.89 89.0 94.0 11.9 71 108.0 225.0 0.46 0.44 8

SS11 12/5/2017 7.02 90.8 10.1 138.3 288.0 0.46 0.45

SS11 1/31/2018 6.91 88.0 9.2 61 99.1 207.0 0.48 0.42 8 <0.05 <0.01

SS11 3/19/2018 7.18 85.2 9.8 188.0 0.58 0.53

SS11 4/9/2018 6.94 87.0 10.3 55 204.0 0.45 0.44 10

SS11 Avg 2017-2018 7.0 87.9 94.0 11.7 61.0 108.1 216.7 0.49 0.46 9.8 <0.05 <0.01

SS91 7/24/2017 <0.001 7.03 68.0 13.9 57 86.7 181.4 0.52 0.49 8 <0.05 <0.01

SS91 9/11/2017 6.98 61.6 13.4 81.8 171.3 0.61 0.34

SS91 10/25/2017 <0.001 7.03 60.0 73.0 11.6 49 120.0 250.0 0.63 0.59 7

SS91 12/5/2017 7.11 71.2 9.9 83.4 174.30 0.61 0.59 0.6

SS91 1/30/2018 7.28 83.0 8.4 51 84.8 198.2 0.67 0.61 13 <0.05 <0.01

SS91 3/19/2018 7.28 74.0 9.9 179.0 0.52 0.46

SS91 4/9/2018 7.38 80.0 10.5 60 195.0 0.60 0.51 13

SS91 Avg 2017-2018 7.2 71.1 73.0 11.1 54.3 91.3 192.7 0.6 0.5 0.6 10.3 <0.05 <0.01


5

Site Date Lead

(mg/L) pH

Alkalinity (mg/L

CaCO3)

Hardness (mg/L

CaCO3) Temp °C

Calcium (mg/L)

TDS (mg/L)


(µS/cm)



Chloride (mg/L)

Sulfate (mg/L)

Iron (mg/L)

Man-ganese (mg/L)

Silica (mg/L)

SS30 7/24/2017 <0.001 7.12 96.0 20.5 80 111.8 233.0 0.61 0.51 9 <0.05 <0.01

SS30 9/11/2017 7.07 88.4 21.3 99.7 208.0 0.55 0.45

SS30 10/25/2017 <0.001 7.20 63.0 66.0 15.0 43 100.4 210.0 0.47 0.45 5

SS30 12/5/2017 7.67 47.6 10.0 51.7 108.9 0.56 0.53

SS30 1/31/2018 7.31 50.0 8.4 30 59.7 125.5 0.52 0.49 3 <0.05 <0.01

SS30 3/19/2018 7.47 52.4 10.0 123.0 0.45 0.26

SS30 4/9/2018 7.22 65.0 11.4 35 159.0 0.44 0.41 5

SS30 Avg 2017-2018 7.3 66.1 66.0 13.8 47.0 84.7 166.8 0.51 0.44 #DIV/0! 5.5 <0.05 <0.01

SS41 1/27/2011 6.62 58 68 9.5 49 82.2 164.2 0.71 0.66 5 7 <0.1 <0.01 42

SS41 4/20/2011 7.40 84.4 81.6 10.4 42 106.0 212 0.63 0.53 9 12 <0.1 <0.01 45

SS41 7/21/2011 <0.001 7.14 80.8 78.8 12.9 19 102.0 205 0.75 0.68 8 13 <0.1 <0.01 41

SS41 10/6/2011 6.99 62.4 64.4 15.3 41 102.0 205.0 0.56 0.52 6 6 39

SS41 6/13/2013 6.93 41.6 81.2 13.2 176.0

SS41 7/22/2013 6.96 83.6 78.4 14.9 190.0

SS41 4/23/2014 7.21 80.8 79.2 11.9 202.0

SS65 1/27/2011 6.89 59 67 9.6 52 88.6 177.5 0.55 0.52 7 10 <0.1 <0.01 34

SS65 4/20/2011 6.54 52.4 72.4 11.2 46 90.6 181.2 0.55 0.48 8 9 <0.1 <0.01 31

SS65 7/21/2011 <0.001 7.23 50.4 44.8 16.0 15 70.6 141.4 0.71 0.64 7 8 <0.1 0.02 39

SS65 10/6/2011 6.39 42.4 61.6 12.6 47 94.5 188.8 0.47 0.44 8 9 <0.1 <0.01 24

SS65 6/13/2013 7.04 29.6 68.8 15.3 156.0

SS65 7/22/2013 7.29 64.0 51.6 14.3 177.0

SS10 6/13/2013 7.02 30.4 64.8 13.1 159.0

SS10 7/22/2013 7.25 63.2 46.8 12.5 166.0

Documents

City of Lacey 2018 Corrosion Control Evaluation · City of Lacey 2018 Corrosion Control Evaluation 6 1.0 PROJECT BACKGROUND The Lacey Water System was regulated as a medium-sized