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This presentation premiered at WaterSmart Innovations
watersmartinnovations.com
City of Phoenix Water Services Department
EVALUATING WATER CONSERVATION
POTENTIAL WITHIN THE MULTIFAMILY
SECTOR
Why study multifamily water demand?
Background of multifamily developments in Phoenix Types and Trends
Multifamily Data Analysis Data obstacles and complexitiesWater use analysis
What we learned and what is the next phase of research?
OVERVIEW
To gain a better understanding of multifamily water use Needed a better understanding of basic information (per unit use over time) Information for tracking multifamily is complicated - not just the one-to-one
relationship like single family (one meter to one residence)
Where were we at? Water consumption trends for existing multifamily developments (pre-1995)
Where are we at? Changes in water consumption for existing multifamily developments Water consumption for newer multifamily developments (post-1995)
How low can we go? High efficiency indoor and outdoor fixtures Landscape changes – lush vegetation to xeriscape
Inform our future water demand forecasts and projections for water resource planning
WHY STUDY MULTIFAMILY WATER DEMAND?
Average annual rainfal l 7-8 inches
Total Population– 1,502,287
Service Area – 540 square miles
Approximately 2450 developments in database Rental Units – 1500 developments Condominiums – 950 developments
Mult ifamily housing sector accounts for roughly 15% of total water use for Phoenix
PHOENIX CHARACTERISTICS
LegendCity of Phoenix
DEVELOPMENT TYPES
ICI sectors have similar end use characteristics Hospitality (extended stay) Retirement Communities Timeshare Dormitories Correctional Facilities Mixed-use (residential/retail)
POTENTIAL MULTIFAMILY SUBSECTORS
DEVELOPMENTS TYPESMARICOPA COUNTY ASSESSOR DATA
CATEGORIES
Rental Units
5-24 Units
25-99 Units
100+ Units
Duplex, Triplex, Fourplex
Mobile Homes
Condo
Multifamily
Townhouses
Condo/Townhouses
Condo/Townhouse built as separate SF
Condo(High Rise)
Categories used by Phoenix for analysis
Rental Units Unified ownership – records aggregated to development Communal space – pool, clubhouse, laundry facility (newer have in-unit
laundry), landscaped areas, playgrounds Master metered properties Developments with pools 48 % of rental units – some developments have multiple pools
Development with cooling towers 4% of rental units - median build age 45 years old (tend to be older or high rise)
Condominiums Owner-occupied – individual records Combination of townhouse, row houses, patio homes and high-rise Both communal and private space – can have a combination of private and
common pools/landscape within a development Both individually and master metered properties Developments with cooling towers – generally high rise 3% of condominium developments
Developments with pools 75% of condominiums – some development have both common and private pools
DEVELOPMENT CHARACTERISTICS
DEVELOPMENT TRENDS
Developments Built by Decade
0
5
10
15
20
25
30
35
Pre-1940 1940-1949 1950-1959 1960-1969 1970-1979 1980-1989 1990-1999 2000-2009 2010-2015
Perc
ent D
evel
opm
ent
Condo Rental
95% of Condo’s were built between 1960-2009
79% of Rental’s were built between 1960-1989
DEVELOPMENT TRENDS
Number of Units by Decade
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
Pre-1940 1940's 1950's 1960's 1970's 1980's 1990's 2000's
Units
Condo Rental
Large inventory –overbuild of rental units
in the 1980’s
DEVELOPMENT TRENDS
0
10
20
30
40
50
60
70
80
90
100
Pre-1940 1940-1949 1950-1959 1960-1969 1970-1979 1980-1989 1990-1999 2000-2009 2010-2015
PER
CEN
T O
F D
EVEL
OPM
ENTS
5-9 Units 10-15 Units 16-50 Units 51-100 Units 100-200 Units 200+
Rental Unit Type by DecadeNewer rental development consist of more units.
Existing rental developments consist of fewer units.
DEVELOPMENT TREND BY AVERAGE UNIT SIZE
0
500
1,000
1,500
2,000
2,500
3,000
Standard Unit Size (60’s to 80’s)
Sample of Developments (post-1998) in Phoenix
Uni
t Siz
e (s
q. ft
.)
DEVELOPMENT TREND BY PLUMBING FIXTURE COUNT
0
5
10
15
20
25
30
Old Expected MF Count
Expected Single Family Count
Num
ber o
f Fix
ture
s
Sample of Developments (post-1998) in Phoenix
Data Complexities Multiple Sources different structures and formats
Association between parcels, water meters and multifamily developments Different types of relationships between parcels and meters One to one, one to many, many to many
DATA COMPLEXITIES
One to One One to Many Many to Many
DATA OBSTACLESUSING GIS TO CREATE
MULTIFAMILY DEVELOPMENTS
Meters not associated with all
parcels in development
Dissolved into single
development
Individual Parcels
WATER USE TRENDS
Number of Units versus Aggregate Water Use (Rental Units)
0
20000
40000
60000
80000
100000
120000
140000
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Num
ber o
f Uni
ts
Mill
ion
Gal
lons
Total Water Use Units
WATER USE TRENDS
0
1000
2000
3000
4000
5000
6000
0
10000
20000
30000
40000
50000
60000
Mill
ions
Gal
lons
Num
ber o
f Uni
ts
Total Water Use Units
Number of Units versus Aggregate Water Use (Condo’s)
WATER USE TRENDS
0
50
100
150
200
250
300
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
GPD
per
Uni
t
Pre-1995
Historical Average Water Use (Multifamily Developments pre-1995)
LANDSCAPE ANALYSIS
Multifamily Landscapes
LANDSCAPE ANALYSIS
Landscapes are changing over time Shift from turf to more
arid landscape Shift from pool to no
pools
How many developments are changing and at what rate?
Is the transition in landscape more dominant in different multifamily development types?
2010 2014
Lush vegetation with turf Arid landscape with a few trees
LANDSCAPE ANALYSISEVALUATING LANDSCAPE TRANSITIONS
Determining landscape characteristics using aerial imagery – remote sensing/visual interpretation Multiple year, high resolution, 4-band imagery
Categorizing based on landscape characteristics Vegetation amount, vegetation type, presence/size of pool
• Turf = 279 m2
• Trees = 46 m2
• Pools = 44 m2
• Parcel = 1669 m2
LANDSCAPE ANALYSIS
Evaluating Landscapes in Multifamily over Time
0
100000
200000
300000
400000
500000
600000
700000
800000
900000
2010 2013
m2
Total Turf Area
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
2010 2013
CCF
Total Water Consumption
*Preliminary data for overall trend – still calibrating methods and analyzing data
Sample of 580 multifamily developments rental and
condominium
Using the calculated vegetation area from remote sensing to compare overall trends temporally and
spatially
Include site specific data Site visits/audits
occupancy rates, number of residents, types of fixtures, amenities (pools, laundry, etc.)
Datalogging Differentiate fixture types
Landscape characteristics landscape classification
Imagery analysis/coding system
Expand inventory for multifamily subsectors
Refine water demand forecasts
ONGOING/FUTURE RESEARCH
What we know? Majority of multifamily developments are older (in age), smaller (average unit
size) and have fewer total number of units (50 or less units)
Newer developments tend to be larger (average unit size), more total number of units per development (100+) and generally have more efficient fixtures (due to efficiency standards)
Multifamily water consumption is gradually declining even with an increase in the number of units and/or developments
Existing developments (pre-1995) have a higher GPD per unit than newer developments (post-1995)
New developments tend to have less water intensive landscapes (more arid/sparse)
Existing developments appear to be transitioning from more water intensive to less intensive landscapes
WHAT WE KNOW?
What’s Next? Delve deeper into the key drivers of water decline Appliances, fixtures, landscaping
How fast are existing developments replacing inefficient fixtures?
How fast are developments changing to even more efficient standards (products on the market that exceed current efficiency standards)?
What are the drivers behind the transition to less water intensive landscapes (arid)?
WHAT IS THE NEXT PHASE?
City of Phoenix Water Services Department
EVALUATING WATER CONSERVATION
POTENTIAL WITHIN THE MULTIFAMILY
SECTOR
Jamie Campbell Planner II
