Rainwater Harvesting Retrofit Strategies: A Guide for Apartment Owners

1. C O N S E RVAT I O N
OVERVIEW OF RETROFIT STRATEGIES
A Guide for Apartment Owners and Managers
U.S. Department of Housing and Urban Development
Office of Policy Development and Research

3. C O N S E RVAT I O N
OVERVIEW OF RETROFIT STRATEGIES
A GUIDE FOR APARTMENT OWNERS AND MANAGERS
PREPARED FOR:
U.S. Department of Housing and Urban Development
Office of Policy Development and Research
Washington, D.C.
PREPARED BY:
Water Resources Engineering, Inc.
San Francisco, CA
IN COLLABORATION WITH:
Public Affairs Management
Allan Dietemann
Jack Goodman
Tony Gregg
John Nelson
M AY 2 0 0 2

5. ACKNOWLEDGEMENTS
This guide was prepared by Water Resources Engineering, Inc. (WRE), San Francisco,
California, for the U.S. Department of Housing and Urban Development (HUD). It was
written by Gustavo Arboleda with assistance from Melinda Goldman. Dana Bress of HUD
provided technical review. Julie Ortiz and Sony Atmadjaja with Public Affairs Management
edited and created the design and layout of the guide. Special thanks go to Allan Dietemann,
Program Manager for the Water Conservation Office of the city of Seattle’s Public Utilities;
Jack Goodman of Hartrey Advisors; Tony Gregg, Manager of the Water Conservation
Program, City of Austin, Texas; and John Nelson of Water Resources Management for their
assistance and guidance throughout this project.
Disclaimer
While the information in this guide is believed to be accurate, neither the authors, reviewers, nor HUD make
any warranty, guarantee, or representation, expressed or implied, with respect to the accuracy, effectiveness, or use-
fulness of any information, method, or material in this document, or assume any liability for the use of any infor-
mation, methods, or materials disclosed herein, or for damages arising from such use.
The U.S. Government does not endorse products or manufacturers. Trade or manufacturers names appear herein
solely because they are considered essential to the object of this project.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S

7. CONTENTS
INTRODUCTION ..........................................................................1
RETROFIT STRATEGIES ................................................................5
SELECTING RETROFIT STRATEGIES ..............................................13
RETROFIT SAVINGS AND COST ....................................................21
REFERENCES ...........................................................................23
APPENDICES
A. H O W M U C H W AT E R IS U S E D I N D O O R S ? ........................................27
B. W AT E R C O N S E R VAT I O N I N C E N T I V E S ............................................29
C. S U B M E T E R I N G R E G U L AT I O N S ....................................................36
D. G R AY W AT E R R E G U L AT I O N S .....................................................40
O V E R V I E W O F R E T R O F I T S T R AT E G I E S

9. INTRODUCTION
Close to a fifth of the United States popula- This guidebook refers to hardware measures
tion lives in multi-family rental housing. as retrofit strategies. Retrofit
Most of these residents do not pay a water To provide with parts,
Where tenant incentive to conserve water
bill. Water charges are embedded in their rent devices, or equipment
may be lacking, owners/managers of multi-
and residents are usually free to use as much not in existence or avail-
family properties must rely on retrofit strate-
water as they wish without additional charge. able at time of original
gies to reduce water consumption and manufacture. To install
Water represents a significant amount of the associated operating costs. or fit a device for use in
cost involved in operating multi-family hous- an existing structure,
Lowering water use in older multi-family
ing. In addition to the actual cost of water are especially an older
properties presents some challenges.
associated costs for the treatment of waste- dwelling.
Extensive renovation may not be economi-
water and the energy required to heat the wa-
cally viable for the many properties whose
ter. These expenses are likely to increase as
housing units have obsolete, non-conserving
groundwater and surface water reserves dwin-
water fixtures and appliances. Retrofit strate-
dle, energy costs rise, and treatment require-
gies, on the other hand, are less invasive and
ments become more stringent.
may be better suited for older structures.
This guidebook is intended to help owners
Retrofit strategies include the repair/and or
and managers of multi-family properties ad-
replacement of showerheads, faucets, toilets,
dress these challenges through water conser-
clothes washers, water meters, irrigation sys-
vation. A companion guidebook directed to
tems, and other features. Specific measures
engineers, contractors, and others responsi-
may range in complexity from simply screw-
ble for the actual design and implementation
ing an aerator on a faucet to installing gray
of water conservation retrofit strategies is
water systems that require storage tanks, fil-
also available from HUD.
ters, pumps, and pipes.
Two types of water conservation strategies
are generally recognized: WHY CONSERVE WATER?
■ Behavioral changes to educate and moti-
vate people to become conservation-con- As the world’s population grows and water
scious and engage in conserving practices demand increases, many regions across the
■ Hardware measures to modify, repair, or
United States will face the hard realities of
remove/replace water-using fixtures or groundwater depletion, chronic drought,
appliances. dried-up rivers, poor water quality, mount-
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 1

10. INTRODUCTION
C O N S E RVAT I O N
ing infrastructure costs, and diminishing al- ■ Type, age, and condition of water-using
ternatives for additional supplies. Water fixtures
treatment facilities are quickly approaching ■ Climate
their treatment capacity due to the increases ■ Price of water where the residents pay di-
in water demand. These constraints are plac- rectly for water used.
ing limits on how much water will be avail-
Outdoor water use is highly site-specific and
able and affordable in the future.
depends on the square footage of landscaped
Water conservation can: areas and the efficiency of irrigation systems
Water ■ Make more water available during and procedures. The type of water-using
Conservation droughts or periods of limited supply recreational facilities will also impact the
is defined as any action ■ Delay the expansion of existing treat- volume of water used outdoors.
that reduces the amount ment facilities and the construction of
of water withdrawn from
water supply sources, re-
new ones INDOOR USE
■ Lower energy consumption by reducing
duces consumptive use, The volume of water used in a typical non-
water heating and treatment needs
reduces the loss or waste conserving housing unit can range from
■ Lower water and energy bills through
of water, improves the
more efficient use of water both indoors around 80 gallons per day to 150 gallons or
efficiency of water use,
and in common and outdoor areas more, depending on the variables noted
increases recycling and
■ Increase property values through the
above. Two adults living in an apartment
reuse of water, or pre-
vents pollution of water. modernization of water-using fixtures, with non-conserving fixtures/appliances may
appliances, and equipment. use about 56 gallons per person each day.
New Mexico Office of the
The distribution of water uses shown in
State Engineer,1997
WATER USE IN MULTI-FAMILY Figure 1 is based on apartments with one
toilet, one showerhead, two faucets, and
HOUSING standard efficiency clothes and dish washers.
An apartment building typically has both in- It is also based on a number of assumptions
door and outdoor water uses. Indoor water regarding how often each fixture or appli-
use is primarily by the occupants of the ance is used. See Appendix A for a complete
housing units, through the use of toilets, listing of the assumptions.
showers, bathroom and kitchen faucets, and
in some cases clothes and dishwashers. INDOOR CONSERVATION
Outdoor water is for areas that may include POTENTIAL
landscaping and recreational facilities such
as swimming pools, spas, fountains, and Indoor water use can be significantly reduced
ponds. In some apartment buildings out- by repairing leaks and installing low water
door uses may include washing cars on the use fixtures and appliances. If the non-con-
premises. serving apartment whose water use is illus-
trated in Figure 1 were retrofitted with faucet
Several factors affect indoor water use:
aerators, a low flow showerhead, an ultra-low
■ Number, age, and income level of occu-
flush volume toilet (ULFT) and high effi-
pants in a housing unit
ciency clothes and dish washers, the total wa-
2

11. INTRODUCTION
ter use per day may come down to about 33 Figure 1 illustrates the volumes of water
gallons per person per day, or roughly 66 gal- used in a typical water-conserving apart-
lons per day for the two-occupant apart- ment. The assumptions made on types of
ment. This represents a savings of 46 gallons fixtures and frequency of use are listed in
per day for one apartment, or about 40 per- Appendix A.
cent of the non-conserving water use.
Figure 1. Typical Water Use in Apartment Units
NON-CONSERVING CONSERVING
Fixture GPCD Fixture GPCD
Toilet 14.0 Toilet 8.0
Note
Faucets 14.0 Faucets 10.5
Approximate volumes of
Shower 11.3 Shower 6.8
water used in gallons per
Clothes Washer 12.0 Clothes Washer 7.5 capita per day or “gpcd”
Dishwasher 1.0 Dishwasher 0.5
Leaks 3.4
Total 55.7 Total 33.3
15 14.0 14.0
12.0
12 11.3
10.5
9
WATER USE (GPCD)
8.0
7.5
6.8
6
3.4
3
1.0
0.5 0.0
0
TOILET FAUCET SHOWER CLOTHES DISHWASHER LEAKS
WASHER
NON-CONSERVING CONSERVING
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 3

12. INTRODUCTION
C O N S E RVAT I O N
OUTDOOR USE multi-family housing sites, based on analysis
of 32 properties across three states (Florida,
The volume of water used outdoors varies California, and Texas).
from one property to another, depending on
Lawns are popular in many regions of the
the amenities offered and the square footage
country and generally use considerable
of landscaping and turf areas. Outdoor wa-
amounts of water. The actual volume of wa-
ter use in properties with extensive landscap-
ter used depends on factors such as the
ing and lawns may represent more than 20
amount and frequency of rainfall, extent and
percent of the total water consumption,
root depth of turf grass, soil type, consump-
while outdoor water uses may account for
tive use requirements, efficiency of applica-
less than 5 percent of total consumption in
tion methods, and maintenance practices.
properties with little or no landscaping. A
Annual water use for lawns reaches peak de-
1999 study prepared for the National
mand during hot summer months and low
Apartment Association and the National
or no demand in cold weather months.
Multi Housing Council found that common
usage (primarily outdoor water use not at-
tributable to apartment residents) averages
OUTDOOR CONSERVATION
from 14 to 18 percent of total water use at POTENTIAL
Multi-family properties with extensive out-
door water use can save water reducing lawn
areas, eliminating narrow strips of turf, us-
ing efficient irrigation methods, metering
outdoor water use separately, and using na-
tive plants with low water consumption in
landscaped areas. Limiting outdoor uses
such as car washing can also contribute sig-
nificantly to water savings.
Using efficient irrigation practices and limit-
ing outdoor water use could reduce outdoor
water consumption by a third or more.
Actual water savings will differ from one
property to another and must be evaluated
on a case-by-case basis.
As a point of reference: one inch of irrigation over a landscaped
area of 1,000 square feet requires 624 gallons of water. How big
is an area of 1,000 square feet? Roughly the size of half a singles
tennis court.
4

13. RETROFIT STRATEGIES
Indoor Retrofit Strategies A variety of water conservation retrofit
strategies are available to multi-family prop-
Quick payback strategies
erty owners. Traditional retrofit strategies in-
• Low-flow faucet aerators clude a number of indoor and outdoor
• Low-flow showerheads measures. Less traditional strategies are also
• Toilet inserts available that involve the use of gray water
• Leak detection and repair for toilet flushing and/or irrigation.
Utility financed strategies
• Toilets through direct-install programs INDOOR WATER USE
• Install devices available free of charge in From a multi-family property owner’s per-
water conservation kits
spective, the most advantageous water con-
Strategies involving utility rebates servation retrofit strategies are those with
Strategies involving manufacturer discounts quick investment paybacks or those paid for
Submetering by local water utilities. Utility financed alter-
natives, of course, are only available to prop-
Outdoor Retrofit Strategies erty owners within the service areas of
Eliminate narrow strips of turf utilities that offer such programs. Appendix
B lists some of the water utilities across the
Reduce lawn areas
United States that offer economic incentives
Use separate water meters for implementing water conservation meas-
Install soil moisture or rain sensors ures. Property owners in other areas should
Install special hose bibs consult with their local utilities about the
Replace sprinklers with drip irrigation systems feasibility of obtaining financial incentives or
credits for installing water-conserving fix-
Landscape with native plants
tures and appliances.
Gray Water Use Strategies
Quick Payback Strategies
Install rainwater collection systems
Recycle water for landscape Retrofit strategies that involve relatively mod-
Install hybrid rainwater collection and recycling est investments and quick paybacks from sav-
systems ings on water and sewer bills include:
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 5

14. RETROFIT STRATEGIES
C O N S E RVAT I O N
■ Low-Flow Faucet Aerators install. They may save between 2 to 4 gal-
lons per day per retrofitted toilet.
Screw-on aerators for bathroom and kitchen
faucets are generally available in hardware The water level in the toilet tank can be ad-
stores for under $2. Property managers or justed to use less water per flush. Water level
residents can install the aerators with mini- adjustments can best be accomplished using
mum effort. Aerators may save from half a a dual-flush adapter, a device that provides
gallon to over 4.5 gallons per faucet per day. for short or long flushes. Adapters may cost
between $8 and $20 and take about 20 min-
■ Low-Flow Showerheads utes to install. Water level adjustments may
save from 1 to 3 gallons per toilet per day.
Low-flow showerheads (flow rate of 2.5 gal-
lons per minute or lower) are available for as ■ Leak Detection and Repair
little as $2, although some of the fancier mod-
els can cost upward of $20. Their installation Toilet, faucet, and showerhead leaks are easy
involves unscrewing the old showerhead and to detect and repair. The repair of faucets
replacing it with the low-flow model. The re- and showerheads generally involves a gasket
placement of non-conserving showerheads replacement (costs under one dollar), which
with low-flow fixtures may save between 3 a handyman can perform in under 15 min-
Courtesy of
Niagara Conservation and 6 gallons per showerhead per day. utes. Toilets usually leak because of defective
flapper valves; flapper valves can be installed
■ Toilet Inserts for $10 or less in under 20 minutes (the ap-
propriate flapper for the toilet model should
Three types of toilet inserts can be imple- be used or leaking may continue). The water
mented at relatively low cost. savings from leak repairs can be significant.
Displacement devices (blocks or bottles Severe leaks, more common in toilets than
placed inside the toilet tank to take up space in other fixtures, can drain over 100 gallons
formerly occupied by water) can be pur- per day. Even modest leaks can lose 3 to 7
chased for under one dollar; installation re- gallons per day per toilet and about a gallon
quires only the lifting of the toilet tank lid per day per faucet or showerhead.
and the placement of the device inside the
tank. Displacement devices may save from 1
Utility-Financed Strategies
to 3 gallons per toilet per day; they should
■ Toilets Through Direct-Install
only be used in toilets with large tanks (5
Courtesy of gallons or more). Programs
Niagara Conservation
The flapper valve inside the toilet tank (the Many water utilities across the country have
device that lifts up to allow water from the recognized the water savings potential of
tank into the bowl) can be replaced with a ultra-low flush toilets (ULFT) and offer in-
quick-closing flapper designed to clamp centives to replace old toilets with water-
down before the tank is emptied. Flapper conserving fixtures. ULFTs are toilets
valves cost between $2 and $10 and take a designed to use 1.6 gallons per flush or less,
plumber or handyman under 20 minutes to compared to the 3.5 gallons per flush or
6

15. RETROFIT STRATEGIES
higher in toilets manufactured before 1992. ample, the East Bay Municipal Utility
The design of ULFTs, and the levels of user District (Oakland, California), the City of
satisfaction, have consistently improved Seattle (Washington), and the City of Tampa
since 1992, when the Energy Policy Act es- (Florida) offer up to $100; the City of
tablished the national manufacturing stan- Albuquerque (New Mexico) and the
dard of 1.6 gallons per flush for most toilets. Metropolitan Water District of Southern
ULFT direct-install program details change California offer $75. Property owners need
from one location to the next (see Appendix to check with their local utilities even in the
B). Owners are sometimes given a choice of locations quoted, because program details
model. A contractor retained by the utility change constantly and their availability may
usually installs the toilets, although some di- be discontinued.
rect-install programs call for installation by
Rebates for the installation of high efficiency
the property owner with rebates offered for
clothes washers currently ranges between $75
each confirmed installation. ULFTs can save
and $150 per in-unit washer, and from $50
between 10 to 20 gallons per toilet per day.
to $250 for commercial washers in common
■ Devices Through Water Conservation laundry areas. For example, the East Bay
Municipal Utility District (Oakland,
Kits
California) offers rebates of $150/$50; the
Many water utilities in the United States of- City of Seattle (Washington) offers rebates of
fer water conservation kits to customers in $75 for in-unit washers and from $150 to
their service areas (see Appendix B). The kits $250 for coin-operated machines; and the
generally include two or three faucet aera- City of Austin, Texas, offers rebates of up to
tors, a low-flow showerhead, toilet displace- $250 on high-efficiency washers.
ment devices, leak detection tablets for
toilets, and informational materials. Property
Discounts
owners should undertake installation of the Property owners may be able to obtain high
water conserving devices with their own per- volume discounts on the purchase of ULFTs
sonnel, rather than leave it up to the resi- and high efficiency clothes washers. They
dents to obtain the full water savings from may also be able to obtain discounts from
the free devices. contractors on multiple installations.
Manufacturers or their local representatives
Rebates
should be contacted for information on high
A number of utilities promote the use of ul- volume discounts.
tra-low flush toilets and high efficiency
clothes washers through rebate programs.
Submetering
The details of each program vary from one Submetering refers to the installation of wa-
location to the next (see Appendix B). ter meters on the water supply lines to each
In ULFT rebate programs the property apartment. The meters track the water con-
owner is typically responsible for the toilet sumption of each unit, and the residents are
installation costs. Rebates currently offered responsible for their own water bills. Water Courtesy of
is thus billed according to the amount Neptune Meters
range from $40 to $100 per toilet. For ex-
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 7

16. RETROFIT STRATEGIES
C O N S E RVAT I O N
consumed — the same fashion that electric- month per unit. Some states, such as Texas,
ity and gas have been billed for years. do not allow the operation and maintenance
costs to be passed on to the residents. Texas
There may be regulations on local or state
also requires either direct utility metering or
water codes that prohibit sub-metering. The
submetering for all apartment units con-
states of Massachusetts and New Jersey, for
structed after January 1, 2003.
example, explicitly prohibit submetering; reg-
ulations are pending in North Carolina. The volume of water saved by the imple-
Some municipalities do not allow submeter- mentation of a submetering system, if any,
ing even if their state water codes do: the city will depend on the cost of water and socioe-
of Augusta does not allow submetering, al- conomic and demographic factors (location,
though the state of Georgia does. The regula- income level, age of residents, etc.). The wa-
tory environment is summarized in Appendix ter savings may vary considerably from one
C. Property owners are urged to verify cur- location to another. One realty company
rent regulations at the local and state level, that owns over 75,000 apartment units
because they will change over time. throughout the country reported average
water savings between 20 and 30 percent of
Property owners have several options when
total use. A submetering study in Seattle did
considering a submetering system:
not record any savings. Reports of minimal
■ Hire a large company with offices na-
savings may be due to the limited conserva-
tionwide
tion options available to residents: fuller
■ Hire a local contractor specialized in sub-
loads in dishwasher, shorter showers, better
metering services
leak reporting. More reliable data may soon
■ Implement the systems on their own, as
be available from an ongoing (2002) na-
some of the larger property owners have
done tional submetering study sponsored by sev-
eral water utilities.
■ Request direct utility metering at apart-
ment units
■ Use a combination of the above.
OUTDOOR WATER USE
The cost of implementing a submeter- Outdoor retrofit strategies involve improv-
ing system may vary among regions of ing irrigation efficiency and limiting outside
the country and even from one prop- water uses. Seven effective means of reduc-
erty to the next. The way water piping ing water consumption are described below.
is laid out in a building can impact
costs. The total cost must also include
Eliminate Narrow Turf Strips
the billing and collection processes, The volume of water saved by eliminating
handling of customer complaints, in- narrow strips of turf will depend on the size
creased maintenance requirements, of the area in question and the material that
and interaction with the local water replaces the lawn: paving/gravel (no water
utility. Based on limited data, imple- use), or plants/shrubs (some water use).
mentation costs may range between $225 Water savings and costs must be estimated
and $500 per unit. Operation and mainte- on a case-by-case basis.
nance costs may fall between $2 and $3 per
8

17. RETROFIT STRATEGIES
A study conducted in Novato, California, cost about $50 per month. If waste-
showed narrow strips of turf required about water charges are based on indoor wa-
four times the amount of water per square ter use, separate meters will have a very
foot applied on larger turf areas. Actual wa- quick payback.
ter savings will vary in different parts of the
country. Property owners should consult Install Soil Moisture or
landscaping and gardening professionals to Rain Sensors
assess water conservation potential.
The Handbook for Water Use and
Reduce Lawn Areas Conservation (Vickers, 2001) estimates
that use of soil moisture sensors/probes or
Smaller lawns save water and may reduce rain sensors can save 5 to 10 percent of water
maintenance costs. This is particularly true used outdoors, provided the oisture/rainfall
in arid and semi-arid areas where the volume data are used to adjust irrigation schedules.
of water used in irrigation can represent a This estimate must be applied on a case-by-
significant proportion of the total water case basis in multi-family properties.
consumption.
The cost of implementing moisture or rain
The water savings and costs associated with sensors will vary depending on the type and
reducing lawn areas depend on the size of quality of devices used. Rain sensors typi-
the area in question and the material that re- cally cost around $25; installation may take
places the lawn: paving/gravel, or plants/ an hour of plumber time and maintenance
shrubs. Water savings from a reduction in costs are minimal. Moisture sensors can
turf areas would only accrue during the pe- range from $10 for a simple resistance probe
riod the lawn is irrigated. to $75 or more for a tensiometer, a device
that measures soil moisture tension by quan-
Use Separate Water Meters tifying the amount of water a plant can draw
While the meters themselves do not save wa- from the soil.
ter, property owner/manager appreciation of
Install Special Hose Bibs
the amounts of water used for common ar-
eas may prompt them to implement one or Hose bibs or outdoor faucets may be retro-
more measures to improve outdoor water fitted with attachments that require a special
use efficiency. Reductions in water use of 5 key to use the outlet. The retrofit costs un-
to 10 percent from the use of separate me- der $10 and may be installed in a few min-
ters are feasible, although actual savings utes by a plumber or handyman.
need to be evaluated on a case-by-case basis.
The volume of water saved by restricting use
The cost of installing separate meters de- of outdoor faucets/hose bibs will be site spe-
pends on the size of the meters. Installation cific. Properties where tenants frequently
charges may be around $100. The water wash cars on the premises would benefit
utility generally charges a monthly fee per most from implementation of this strategy.
meter; a 2-inch meter may cost between $10 Water use can be reduced by 50 percent or
and $20 per month; a 4-inch meter may more at each retrofitted hose bib.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 9

18. RETROFIT STRATEGIES
C O N S E RVAT I O N
Replace Sprinklers with Drip ■ The California Native Plant Society
Irrigation quotes plant costs between $2.25 and
$96
Drip irrigation systems can save 25 to ■ Florida Native Plants.com offers plants
75 percent of the water that a sprinkler between $5 and $45
system would use. Actual savings must ■ The New England Wildflower Society
be determined on a case-by-case basis, sells flowers, shrubs and trees from $5 to
and depend on the type of sprinklers $75 per unit
replaced and the characteristics of the An approximate cost of $2 per square foot
irrigated area. The cost of replacing of area to be planted may be used as a rough
sprinklers with a drip system depends “rule of thumb” estimate. Operation and
on the size of the area to be irrigated maintenance costs should actually decrease
and the type of system installed. The with the native plants, as they are better
Handbook of Water Use and adapted to local conditions than less water-
Conservation estimates the cost of installing efficient plants.
a drip system at $1 to $1.50 per square foot.
Drip systems do require periodic mainte- GRAY WATER USE RETROFIT
nance for efficient operation.
STRATEGIES
Landscape with Native Plants
The least traditional retrofit strategy for wa-
The volume of water saved by using low-wa- ter conservation in a multi-family setting is
ter use and native plants in place of conven- the installation of gray water systems.
tional landscaping needs to be evaluated on
Gray water systems may consist of:
a case-by-case basis. Studies conducted in
■ Rainwater collection
Arizona, California, and Texas found that re-
■ Gray water recycling
placing conventional landscapes with low-
■ Hybrid rainwater collection and recy-
water use and native plants reduced outdoor
water use from 19 percent (North Marin, cling systems
California) to 43 percent (Austin, Texas). In terms of cost effectiveness, hybrid systems
These studies were conducted in single-fam- rank higher than the other two alternatives.
ily homes; savings in multi-family properties Gray water recycling tends to be more cost
may differ depending on maintenance and effective than rainwater collection. The three
irrigation system efficiency. types of gray water systems are described
The cost of replacing high-water-use plants below.
and lawns with low-water use and native Rainwater Collection
plants has to be evaluated on a case-by-case
basis. The New Mexico Office of the State Rainwater collection or rainwater harvesting
Engineer’s Xeriscape 101 pamphlet quotes technology has been around for centuries as
installation costs at $1 to $4 per square foot. a means to use seasonal precipitation that
The cost of the native plants can vary from would otherwise be lost. A rainwater harvest-
$2 to nearly $100 per plant: ing system concentrates and collects rain
10

19. RETROFIT STRATEGIES
Desert House rainwater collection
system in Phoenix, Arizona
(Courtesy of Desert Botanical
Garden, Phoenix Arizona)
falling on roofs and grounds for direct use ally charge between $2 and $4 per gallon of
and storage; water may be collected or har- storage for the installation of a complete
vested from concrete patios, driveways and rainwater harvesting system including under-
other paved areas. The water is typically used ground concrete tank, pump, valves, piping,
for landscape irrigation and/or toilet flushing. and catchment appurtenances. Systems with
Successful implementation of large-scale above ground storage or with polyethilene or
rainwater harvesting systems relies on several fiberglass tanks would be less expensive
factors. Most important is a suitable climate (from $0.40 to $1 per gallon of storage).
that affords periodic rainfall throughout the Multi-family properties are likely to require
year; low rainfall and/or extended dry peri- in excess of 10,000 gallons of storage.
ods limit the reliability and effectiveness of a Rainwater collection systems that provide
rainwater harvesting system. The most eco- water for toilet flushing as well as landscape
nomically viable systems are likely to have irrigation will save more water and cost con-
small storage capacities that supplement siderably more. Separate piping has to be
rather than replace water supplies from local provided from the storage tank to every toilet
utilities. on the property. This requires a significant
The costs of rainwater collection systems investment in the re-plumbing of the build-
vary from one location to another and de- ing. Properties about to be renovated and
pend on the situation and life of the system. new properties, however, may be able to add
Contractors in New Mexico and Texas gener- the additional piping at a relatively low cost.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 11

20. RETROFIT STRATEGIES
C O N S E RVAT I O N
Gray Water Recycling The costs of gray water systems vary, de-
pending on the size and complexity of the
Gray water recycling systems consist of de- system. Costs may range from $3,000–
vices attached to the plumbing system for $5,000 per housing unit for systems that
Gray water the sanitary distribution or use of gray water provide enough water to cover irrigation
means untreated waste- (water from bathroom sinks, showers, and needs. Property owners should consult de-
water which has not clothes washers). These systems require sign professionals to define the size and
been contaminated by pipes separate from the potable water pip- complexity of recycling systems that meet
any toilet discharge, ing, as well as valves, filters, pumps, and their needs, and to assess the return period
has not been affected treatment facilities.
by infectious, contami-
of their potential investment in gray water
nated, or unhealthy Permits are required in most states for the recycling systems.
bodily wastes, and implementation of gray water systems, usu-
Hybrid Systems
which does not present ally from local or county authorities. The
a threat from contami- primary concern of regulators and health of- Hybrid systems use both rainwater and ef-
nation by unhealthful ficials is that gray water may result in water fluent from bathroom sinks, showers, and
processing, manufactur- quality problems that pose a threat to public clothes washers as their source of water. The
ing, or operating health. Regulations invariably prohibit gray source water is typically treated and then
wastes.
water systems from being connected to distributed to irrigation systems and/or toi-
The California Water potable water systems and typically preclude lets. Hybrid systems discharge excess water
Code (Section 14875- the use of water containing hazardous wastes to the sewer.
14877.3) or water that comes from the soiling of dia-
As with simple recycling systems, the hybrid
pers or similar garments.
systems require permits from local health
authorities. Many states allow only under-
ground irrigation with gray water to prevent
human contact with the water.
Hybrid systems can be more cost effective
than simple recycling or rainwater collection
systems. Once the treatment facilities and
related equipment needed for recycling is in
place, the rainwater collection portion of the
system can be added at a relatively low cost.
Property owners should consult design pro-
fessionals to evaluate the desirability of in-
stalling a hybrid gray water system in their
facilities.
Typical gray water system
used for irrigation
(Courtesy of Carl Lindstrom)
12

21. SELECTING
RETROFIT STRATEGIES
A variety of reasons may motivate property WATER USE ASSESSMENT
owners/managers to conserve water:
■ Contribute to the protection of a valued Is your multi-family property conserving or
natural resource non-conserving in terms of water use? If you
■ Avoid potential water shortages in the don’t know for certain, the property is most
future likely non-conserving. The determining fac-
■ Save money. tor is the water bill. An examination of wa-
ter bills and a few simple calculations can
Retrofit strategies also may select themselves.
settle the issue.
If toilets in a multi-family building are over 20
years old and managers are constantly receiv- Water and sewer bills come in many sizes Useful Water
ing complaints about malfunctions and leaks and formats. To assess water use it is impor- Units
the time may be right to replace them. Or tant to determine:
■ Number of days in billing cycle: Most
1 cubic foot (cf) =
clothes washers in the laundry room may be
utilities bill either monthly or bi- 7.48 gallons
out of order and beyond repair. Perhaps low
water pressure in the building points to the monthly; assume 30 days in the billing 1 ccf (commonly used
need for a major overhaul of the water piping. cycle if billed monthly, 60 days if billed by water utilities as
bi-monthly. “one unit”) = 100 cf =
Reacting to a clear need to upgrade water- ■ Volume of water used per billing cycle: 748 gallons
using fixtures and appliances is as valid a Water utilities use either hundreds of cu- 1 liter = 0.26 gallons
reason as any to retrofit and conserve water. bic feet (ccf ) or thousands of gallons as
In some instances, however, retrofitting may the units of measurement to record vol-
present clear advantages even without the ume of water used.
pressing need to upgrade. ■ Is there a separate meter for outdoor
water use? Separate meters may be billed
This section outlines a proactive approach to
separately. If two or more meters are in-
retrofitting for water conservation. It pres-
cluded in one bill the water use from
ents simple guidelines for a property each meter is likely to be prominently
owner/manager to assess water use patterns, displayed.
select retrofit strategies, estimate conserva-
tion potential, and determine approximate With information from the water bills and a
costs and how quickly they can be recovered few facts about occupancy, you can approxi-
from savings in water/sewer bills. mate water use per person. Winter and sum-
mer water use can be compared for a rough
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 13

22. SELECTING RETROFIT STRATEGIES
C O N S E RVAT I O N
approximation of outdoor water use, assum- ence in per capita water usage between win-
ing the property is not irrigated during win- ter and summer months may be attributed
ter months (not always the case in southern to outdoor uses for purposes of obtaining a
states). rough estimate of water use.
More accurate calculations require knowl- Resident-related (indoor) water use may be
edge of the number of building residents qualified as shown in Table 1, below.
(water users) in a given time period. If these
Use of water for landscape irrigation is more
figures are not available, the average number
difficult to qualify, as it depends not only on
of residents over the past few years may be
the efficiency of irrigation systems but also
used to approximate per capita water usage.
on the extent of the facilities. A property
Following are some basic calculations to
with extensive lawns and gardens may use
help assess specific properties.
significant volumes of water even if irrigated
Daily water use for the property = (Number very efficiently.
of ccf in water bill) x 748 / (Number of days
Property owners should consult with their
in billing cycle)
water utility regarding outdoor water audits,
Daily per capita use = Daily water use for or contact a landscaping professional in their
the property / Number of residents area. Many utilities offer audit services free
of charge. The audit involves the physical
The per capita water usage should be calcu-
inspection of the facilities by a utility repre-
lated for several billing cycles, including
sentative who can identify areas in need of
summer and winter periods. The per capita
water-efficiency improvements, recommend
usage in winter months is likely to reflect in-
changes to landscaping, and review irriga-
door water usage. Buildings with no land-
tion practices and procedures.
scaping or significant outdoor water uses
should show similar per capita volumes year-
round. Buildings with significant outdoor INDOOR WATER USES
water uses should show higher water use Strategies may be selected on the basis of
during summer months (except, as previ- property owner preference, conditions spe-
ously noted, in southern states). The differ- cific to the property (for example, toilets
need replacement anyway), availability of re-
Table 1—Indoor Water Use Assessment bates from water utilities, or availability of
special discounts on high volume purchases.
GPCD WATER USE ASSESSMENT The right retrofit strategies may also become
(Gallons per capita per day) apparent from an analysis of the fixtures in
Under 30 Highly efficient water use, no place and the ones that may potentially re-
conservation potential place them.
30-50 Efficient water use, some con- A simplified analysis can be conducted by
servation potential if closer to
filling out Table 2 on the following page.
50 gpcd
Over 50 Non-conserving water use, defi-
The payback periods on Line 13 should be
nite conservation potential evaluated in light of the longevity of the wa-
14

23. SELECTING RETROFIT STRATEGIES
Table 2—Estimate of Indoor Water Conservation Potential, Costs, and Payback
ITEM TOILET FAUCETS SHOWERHEADS CLOTHES WASHER
1. Flush volume in gallons per flush (gpf) _____ gpf _____ gpm _____ gpm _____ g/load
for existing toilets; flow rate in gallons
per minute (gpm) for existing faucets
and showerheads; average water use
per load for existing clothes washers
2. Flush volume, flow rate, or use per load _____ gpf _____ gpm _____ gpm _____ g/load
for water conserving replacements or
toilet inserts
3. Potential reduction in water use _____ gpf _____ gpm _____ gpm _____ g/load
(Subtract Line 2 from Line 1)
4. Daily use for each device (number of _____ flushes _____ min _____ min _____ loads
flushes for toilets; number of minutes
for faucets and showerheads; loads per
day for washers)
5. Water savings in g/day/device (Multiply ___________ ___________ ___________ ___________
Lines 3 and 4)
6. Total number of devices in property ___________ ___________ ___________ ___________
7. Total ccf of water saved per year* ___________ ___________ ___________ ___________
(Multiply Line 5 by Line 6 by 0.488)
8. Cost of water per ccf (from water bill)* ___________ ___________ ___________ ___________
9. Dollars saved per year (Multiple Lines 7 ___________ ___________ ___________ ___________
and 8)
10. Cost of retrofits/replacements ___________ ___________ ___________ ___________
11. Rebate amounts, if any ___________ ___________ ___________ ___________
12. Net costs (Subtract Line 11 from ___________ ___________ ___________ ___________
Line 10)
13. Payback period in years (Divide Line 12 ___________ ___________ ___________ ___________
by Line 9)
* Make appropriate corrections if water bill is in thousands of gallons.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 15

24. SELECTING RETROFIT STRATEGIES
C O N S E RVAT I O N
ter savings obtained from the various conser- place and recording the lowest depth of wa-
vation measures. New toilets may be ex- ter during the flushing process. The differ-
pected to have a useful life of about 20 ence between the full and near-empty tank
years; toilet inserts, however, may last five depths is the height of the water column.
years or less. Faucet aerators and low-flow
To determine flush volume:
showerheads may have a useful life of about
ten years. Clothes washers may last 12 years Multiply the height of the water column
(in-unit) or less (laundry areas). by the tank width and length (all in
inches), and then by 0.0043 to convert
The table may yield some results that require
the result to gallons per flush.
additional investigation, and the following
guidelines are provided to facilitate this re- This measured flush volume is not exact, as
search process. Property owners may be able it does not take into account the water that
to obtain some of the required data from a enters the tank as the toilet is being flushed.
water audit conducted by their water utility. The measurement is sufficiently accurate,
however, for purposes of estimating conser-
Toilet Flush Volumes vation potential, particularly in light of the
fact that several other approximations have
Existing toilets are most likely of the gravity-
to be made.
flush type, that is, they have a tank that dis-
charges water into a bowl after a handle is Ideally all toilets on the property are alike
pulled down. Other types include toilets and one measurement of flush volume will
with pressure-assisted flush and units with suffice. If there are different makes and
flushometer valves, such as the ones found models of toilets, more than one measure-
in airports or commercial buildings. ment may be required. An average flush vol-
ume for all toilets in the building should be
Some gravity flush toilets use over 5 gallons
entered in Table 2.
of water per flush, others use less. The ultra-
low flush type (ULFTs), use 1.6 gallons per The flush volume after retrofits should be
flush or less. If the property already has verified with the manufacturers of the vari-
ULFTs there is no need to consider any toi- ous devices. The following values serve as
let retrofit strategy. If older toilets with general guidelines:
larger flush volumes are in place, their flush ■ Use 1.6 gallons per flush for new toilets
volumes should be determined. ■ Reduce initial flush volume by 0.3 gal-
lons for a displacement device, unless
One of the simplest ways to determine flush
manufacturer specifies a higher number
volume is to measure it. After lifting the toi-
(use displacement devices only in high
let tank lid, a tape measure can be used to flush volume toilets)
determine width and length of the tank. The
■ Reduce initial flush volume by 0.5 gal-
height of the water column used for flushing lons for installation of a quick-closing
can be determined by measuring the depth flapper valve or water level adjustment,
of water before flushing, then flushing the unless manufacturers specify different
toilet while holding the tape measure in numbers.
16

25. SELECTING RETROFIT STRATEGIES
Faucet and Showerhead Flow Clothes Washer Loads
Rates
The gallons per load (also termed “per cy-
Flow rates depend not only on the capacity cle”) used by a washing machine are gener-
of the fixture but also on the available water ally included in the literature that comes
pressure. The same model fixture will have a with the appliance. If the manuals are not
higher flow rate in a building with 80 available, the volumes may be obtained di-
pounds per square inch (psi) of pressure than rectly from the manufacturer.
in a building with 40 psi pressure. If a prop- Older, standard efficiency clothes washers
erty has several buildings with different water use from 33 to over 40 gallons of water per
pressures, the fixtures in each building load (the 33 gallons per load figure is from a
should be treated separately. 1999 study of multi-family common laun-
Flow rates may be measured using a stop- dry areas in Toronto, Canada; a study per-
watch and a specially designed flow-measur- formed for Southern California Edison in
ing bag available in hardware stores or from 2000 found 38 gallons per load; studies in
water utilities. The flow rate is measured by Seattle found over 40 gallons per load).
setting the bag to receive all flow from the Newer, high performance or high efficiency
fixture, opening the faucet or showerhead to clothes washers use considerably less water.
its normal operating range, and allowing flow The 2000 Southern California Edison study
into the bag for a pre-determined number of (conducted by Battelle Pacific Northwest
seconds (specified on the bag, usually five Laboratories) found that Maytag high per-
seconds). The flow rate can then be read di- formance washing machines used on the av-
rectly from markings on the side of the bag. erage 15.4 gallons of water per cycle; the
Speed Queen brand used 17.0 gallons per
The flow rates after retrofits should be veri-
cycle; and Whirlpool high efficiency washers
fied with the manufacturers of the various
used on the average 27.4 gallons per cycle.
devices. The change in flow rate between an
old showerhead and a new one, in particular, Daily Fixture/Appliance Use
could vary widely from one property to the
next. The following values may be used as How many times is a toilet flushed each day?
general guidelines: How many minutes does a faucet or a show-
■ Reduce faucet flow rate by 0.5 gpm for
erhead operate each day? How many loads of
faucet aerators unless manufacturer speci- laundry are done in each washer per day?
fies otherwise; low flow faucets generally These numbers vary from one household to
have flow rates of 2.2 gpm or less. the next. Unfortunately no comprehensive
■ Assume a flow rate reduction of 0.75 study has been conducted at the national
gpm for new showerheads if no other in- level to determine average usage for fixtures
formation is available; low flow shower- in a multi-family setting. Based on available
heads generally have flow rates of 2.5 data, the following guidelines are provided:
gpm or less.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 17

26. SELECTING RETROFIT STRATEGIES
C O N S E RVAT I O N
■ Toilets are flushed roughly 5 times per age number of people per apartment and
person per day (Residential End Uses of multiply it by 0.37 (or other number judged
Water, a study conducted in 1999 for the appropriate to the site in question) to obtain
American Water Works Association, the number of loads per day. If the property
found an average of 5.05 flushes per per- has common area washers, take the number
son per day from measurements in close of residents in the entire property and multi-
to 1,200 single-family homes). If an
ply it by 0.1 to obtain the number of loads
apartment houses two people and has
for all common area machines. Then divide
one toilet, the toilet would be flushed 10
times per day. that number by the number of machines to
obtain the “loads per washer.”
■ Faucet use in apartments may be around
14 minutes per day (from a multi-family
study conducted in Seattle in 1993). If OUTDOOR WATER USES
an apartment has two faucets, the as-
Outdoor and common area water uses in
sumption is that each faucet would be
used for 7 minutes a day. multi-family properties can range from vir-
tually none to over 20 percent of the total
■ Showerhead use in apartments may be
close to 6 minutes per person per day water consumption. Some properties may be
(from the same 1993 multi-family study able to implement all of the seven outdoor
in Seattle). retrofit strategies presented in this guide-
■ Clothes washer use differs markedly be-
book. Others may be limited by the charac-
tween in-unit machines and washers in teristics of their water use to one or two of
common laundry areas. them.
A 2001 study for the Multi-housing If it were feasible to implement the seven
Laundry Association found that the volume retrofit strategies outlined in the previous
of water used for laundry per apartment unit section of this guidebook, in what order of
was almost four times higher in properties preference should they be considered?
that had in-unit clothes washers. Dwellers Again, the analysis may differ from one re-
apparently adjust their laundry habits when gion of the country to another, and property
they have to use common area washers. In- owners are urged to consult with landscap-
unit washers possibly handle between 0.3 ing and water conservation professionals in
and 0.4 loads per person per day their area. A research paper sponsored by
(Residential End Uses of Water found a usage HUD, Retrofit Water Conservation Strategies
of 0.37 loads per person per day in single- for Multi Family Housing (available online at
family homes). Common area washers may www.pathnet.org/publications/water.pdf)
handle about 0.1 loads per person per day suggests the following rankings:
(from the Toronto study). So what number 1. Eliminate narrow strips of turf
should be entered for number of loads of 2. Reduce lawn areas
washing in the fourth row of Table 2? If the 3. Use separate meters for outdoor water
property has in-unit washers, take the aver- uses
18

27. SELECTING RETROFIT STRATEGIES
4. Install soil moisture or rain sensors GRAY WATER
5. Install specially fitted hose bibs to restrict
outdoor water use Gray water systems are becoming increas-
6. Replace sprinklers with drip irrigation ingly attractive, particularly in areas with se-
systems vere water shortages, limited water and
7. Use low water consumption native plants wastewater treatment facilities, and special
environmental concerns (i.e. groundwater
Property owners may also consider the ad-
contamination or highly polluted surface
vantages of another important common-area
waters).
water use: laundry facilities. As noted previ-
ously, transitioning from in-unit clothes Rainwater harvesting is gaining acceptance
washers to common laundry facilities may in several states (Hawaii, Texas, Arizona,
decrease the amount of water used to wash New Mexico) where summer rain is com-
clothes by more than half. mon. In Hawaii County, more than 8,000
homes have rainwater catchment systems.
When selecting outdoors retrofit strategies
The city of Austin, Texas, offers rebates for
property owners should consider that:
the installation of rainwater harvesting sys-
■ Narrow strips of turf use up to four times
tems. A demonstration home in Phoenix,
as much water for irrigation than a lawn
Arizona, illustrates the advantages of rainwa-
of comparable area.
ter harvesting. The city of Albuquerque,
■ One inch of water applied to 1,000
New Mexico, offers a booklet titled
square feet of lawn amounts to 624 gal-
Rainwater Harvesting, Supply From The Sky
lons. In one year a lawn may require 30
that gives system design and construction
inches of irrigation, or 18,720 gallons.
information.
■ Meters on outdoor water uses do not
save any water themselves; they do pro- Rainwater collection for both landscaping
mote conservation by helping property and toilet flushing has been implemented at
owners appreciate the volumes of water a number of facilities in the United States,
used outdoors. primarily office buildings. Among them:
■ Soil moisture and rain sensors are only ef-
■ The King Street Center in Seattle,
fective if the information derived from Washington, a 327,000 square feet office
them is used to adjust watering schedules. building, uses a rainwater collection sys-
■ Restriction of outdoor uses such as car tem for toilet-flushing water.
washing is likely to elicit a negative re- ■ The Chesapeake Bay Foundation build-
sponse from residents upon its introduc- ing in Annapolis, Maryland, features
tion; some properties have dealt with this rooftop cisterns that capture rainwater
issue by offering discount coupons usable for hand washing and fire suppression.
at local car washes. ■ The U.S. Navy Energy Showcase build-
■ Drip irrigation systems significantly re-
ing at the Naval Construction Battalion
duce water use, but also increase mainte- Center in Port Hueneme, California,
nance requirements. uses rainwater for irrigation.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 19

28. SELECTING RETROFIT STRATEGIES
C O N S E RVAT I O N
One multi-family property, a triplex owned tem with a 5,000-gallon storage tank could
by a builder in Seattle, Washington, has in- cost about $20,000 and have limited use in
stalled a rainwater collection system that locations where rainfall is not distributed
provides water for toilet flushing with the evenly throughout the year. For the same
intent of evaluating this technology for $20,000 a property owner would be able to
wider scale use in new construction. install a hybrid system capable of treating
over 100 gallons per day year round. On the
Gray water recycling systems have been im-
other hand, a gray water system without
plemented in multi-family properties in
rainwater collection would cost roughly the
Ottawa and North Vancouver, Canada.
same as a hybrid system. The incremental
Some properties in the United States have
costs of collecting rainwater from rooftop
installed dual piping upon construction to
and driveway catchments are relatively
use gray water in the future for toilet flush-
small.
ing. The EcoVillage Cohousing Cooperative
in Ithaca, New York, is one such property. The cost of installing gray water systems is
relatively high when compared to the cost of
Hybrid systems using both rainwater collec-
other retrofit strategies. Certain site-specific
tion and recycling of gray water for toilet
conditions, however, could favor the selec-
flushing have yet to make an appearance in
tion of such a system:
multi-family housing, although they are
■ Water is extremely scarce and expensive
more cost effective than systems that have
■ There are severe limitations on waste-
rainwater collection or gray water recycling
alone. The cost effectiveness of such systems water discharges
■ The volume of water used for irrigation
may be enhanced in places where the water
storage tanks (the most expensive compo- is over 20 percent of the total water use
■ Internal plumbing is such that retro-
nent of the system after the separate plumb-
ing of toilets) can serve multiple purposes fitting toilet piping is relatively easy
such as detention storage to reduce flooding ■ The property is required to store water
and erosion from storm water discharges. for flood and erosion control purposes
■ Local utilities offer rebates for the instal-
Which gray water system, if any, is right for lation of gray water systems.
a property? A hybrid system that includes
both rainwater collection and gray water re- Property owners are advised to check local
cycling is likely to be the most advanta- health regulations and water codes before
geous. A rainwater collection system by itself consideration of gray water systems. A list-
will have limited use and a relatively high ing of applicable statutes is included in
cost of up to $4 per gallon of storage. A sys- Appendix D.
20

29. RETROFIT SAVINGS
AND COST
When properly implemented and main- proponents of selected retrofit strategies, and
tained, the strategies discussed in this guide- research organizations. Studies of multi-
book are very likely to conserve water and family properties and single-family homes
lower water, sewer, and power bills. An ini- were examined.
tial, sometimes significant investment of
None of the estimates has universal applica-
time and money is required to obtain the
bility, but are included to serve as a guide in
water savings. Money spent on retrofits can
the preliminary evaluation of the merits of
sometimes be recovered within two years
retrofit strategies in multi-family properties.
and in other cases over a longer time frame.
Other important points to note:
Quantifying water savings and implementa-
■ The table includes water savings in gal-
tion costs is difficult. The physical condi-
lons per year. For indoor and outdoor
tions affecting retrofit strategies change from water uses involving devices, the savings
one property to the next. Labor and material are per device (toilet, faucet, showerhead,
costs can also vary markedly from one re- clothes washer). For outdoor water uses
gion to another. These challenges are com- involving irrigation the savings are per
pounded by the lack of studies in multi- thousand square feet of area irrigated 30
family settings with results that are applica- inches per year.
ble at the national level. ■ Estimated implementation costs include
device and labor costs. Labor costs were
Difficulties notwithstanding, estimated wa-
estimated assuming plumbers at Full details on how the wa-
ter savings and costs for the retrofit strate-
$60/hour and technicians/laborers at ter savings and costs fig-
gies outlined in this guidebook (other than $36/hour. ures were determined are
gray water systems) are presented in Table 3. available in Retrofit Water
■ The “ease of implementation” is a subjec-
Water savings will usually fall within the tive factor indicating relative difficulty. Conservation Strategies for
specified ranges but could easily be higher or The strategies easiest to implement were Multi-Family Housing, avail-
lower at some properties. given an “ease” factor of 1.0; the lower able at
the factor the more difficult to imple- www.pathnet.org/publica-
The estimates were derived from data avail-
ment. tions/water.pdf
able through multiple sources. Information
■ The “longevity” of a measure is a rough
was gathered with the collaboration of vari-
ous water utilities, companies offering retro- approximation of the useful life of a
fit services or devices, supporters and retrofit. Twenty years was used as the
base for the longer lasting strategies.
O V E R V I E W O F R E T R O F I T S T R AT E G I E S 21