_ High-Efficiency Lavatory Faucet Specification
Water Sense Supporting Statement
WaterSenseฎ High-Efficiency Lavatory Faucet Specification
Supporting Statement
I. Introduction
The WaterSense program released its High-Efficiency Lavatory1 Faucet Specification
(specification) on October 1, 2007, to promote and enhance the market for water-efficient
lavatory faucets. The goal of this specification is to allow consumers to identify and differentiate
products in the marketplace that meet this specification's criteria for water efficiency and
performance.
This specification addresses lavatory faucets and lavatory faucet accessories2 in private use,
such as those found in residences, and private restrooms in hotels and hospitals. Since these
types of faucets are used primarily for hand washing and other sanitary activities, such as face
washing and razor rinsing, WaterSense believes that maximum flow rates can be reduced
enough to impact national water consumption while at the same time not negatively impacting
user satisfaction. This specification is not intended to address kitchen faucets, which have a
very different set of uses and performance criteria, or public restroom faucets (e.g., airports,
theaters, arenas, stadiums, offices, and restaurants), which already have national performance
standards and criteria to which they should conform.
II. Current Status of Faucets
WaterSense estimates that currently there are 222 million residential lavatory faucets in the
United States. This estimate is based on an assumed one-to-one ratio of lavatory faucets to
residential bathrooms.3 In addition to the existing stock, approximately 25 million new faucets
are sold each year for installation in new homes or replacement of aging fixtures in existing
homes.4 Of these 25 million faucets, roughly two-thirds of those are lavatory faucets
(approximately 17 million units). Residential lavatory and kitchen faucets account for
1 Lavatory is the terminology used in the Energy Policy Act of 1992 and ASME A112.18.1 to describe the
types of faucets to which the standards apply. In this specification, lavatory means any bathroom sink
faucets intended for private use.
2 Accessory, as defined in ASME 112.18.1, means a component that can, at the discretion of the user, be
readily added, removed, or replaced, and that, when removed, will not prevent the fitting from fulfilling its
primary function. For the purpose of this specification, an accessory can include, but is not limited to
lavatory faucet flow restrictors, flow regulators, aerator devices, laminar devices, and pressure
compensating devices.
3 U.S. Census Bureau, American Housing Surveys for the United States, 1970-2003.
4 Business Trend Analysts, 2006. "2005/2006 Outlook for the U.S. Plumbing Fixtures and Fittings
Industry."
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
approximately 15.7 percent of indoor residential water use in the United States5equivalent to
more than 1.1 trillion gallons of water used each year.
The Energy Policy Act of 1992 originally set the maximum flow rate for both lavatory and kitchen
faucets at 2.5 gallons per minute (gpm) at 80 pounds per square inch (psi) static pressure. In
1994, American Society of Mechanical Engineers (ASME) A112.18.1M-1994-Plumbing Supply
Fittings set the maximum flow rate for lavatory faucets at 2.2 gpm at 60 psi. In response to
industry requests for conformity with a single standard, in 1998, the U.S. Department of Energy
adopted the 2.2 gpm at 60 psi maximum flow rate standard for all faucets (see 63 FR 13307;
March 18, 1998). This national standard is codified in the U.S. Code of Federal Regulations at
10 CFR Part 430.32. As a point of reference, the maximum flow rates of many of the pre-1992
faucets range from 3 to 7 gpm. Other than the aforementioned maximum flow rate standards,
there currently are no universally accepted performance tests or specifications (e.g., rinsing or
wetting performance standards) for faucets.
III. WaterSense High-Efficiency Lavatory Faucet Specification
The WaterSense program developed this specification to address criteria for improvement and
recognition of water-efficient and high-performance lavatory faucets and lavatory faucet
accessories. WaterSense labeled lavatory faucet accessories can be incorporated into the
design of new faucets to control the flow rate and provide the mechanism for meeting this
specification's criteria, or can be purchased separately and retrofit onto existing older faucets to
provide water efficiency and performance. This specification focuses solely on the category of
lavatory faucets intended for private use because of the differences in the uses and
performance expectations between private lavatory faucets and kitchen or public restroom
faucets. Lavatory faucets are used primarily for hand washing and other sanitary activities, such
as teeth brushing, face washing, and shaving. For these activities, discussions with faucet
manufacturers and water utility representatives provided a general consensus that a reduction
in the maximum flow rate from 2.2 gpm (the current federal water-efficiency standard) to 1.5
gpm, as established by this specification, is not very noticeable for most users. The most
noticeable differences are increased wait times when filling the basin or waiting for hot water.
While decreasing a faucet's maximum flow rate increases user wait time for these activities,
WaterSense determined the potential water savings gained from the primary use of lavatory
faucets (i.e., washing and rinsing) outweigh any potential inconvenience caused by increased
wait times and will not negatively impact overall user satisfaction.
Kitchen sink faucets were excluded from this specification because the different uses and user
expectations require other considerations for defining performance. One major performance
consideration is a kitchen faucet's ability to effectively rinse dishes. Kitchen faucets also are
commonly used for pot or container filling, and significantly increased wait times might not be
acceptable to most users. WaterSense determined that reducing the maximum flow rates of
kitchen faucets would create issues of user satisfaction and be counter to its program goals of
5 Mayer, Peter W. and William B. DeOreo. Residential End Uses of Water. Aquacraft, Inc. Water
Engineering and Management. American Waterworks Association. 1998.
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
increasing efficiency while maintaining or improving performance. In order to maintain user
satisfaction and ensure a high level of performance, a maximum flow rate greater than what is
suitable for lavatory faucets might need to be considered for kitchen faucets. Some type of
wetting or rinsing performance test also might need to be included. In addition, there is an
emerging area of research and development in multiposition control lever faucet technologies
that offer users "high" and "low" settings for different activities. While performance data are not
yet available, these technologies might prove to be effective in using water more efficiently. For
these reasons, WaterSense intends to evaluate the possibility of developing a WaterSense
specification for kitchen faucets at a later date.
Public restroom and metering faucets (faucets that are set to discharge a specific amount of
water or run for a specified period of time for each use) also were excluded from this
specification because of their differing uses and performance expectations and because
standards governing their maximum flow rate already exist. Public restroom faucets, for
example, are used almost exclusively for hand washing or simple rinsing, compared to lavatory
faucets in homes and in other private bathrooms that face a myriad of uses. As a consequence,
the maximum flow rate for these public restroom and metering fixtures can be set significantly
lower than the flow rate for private lavatory faucets without negatively impacting user
satisfaction. Also, a separate set of standards already apply to these types of fixtures. Codified
in the U.S. Code of Federal Regulations at 10 CFR Part 430 (specifically ง430.32(o) Faucets)
are standards setting the maximum flow rate for metering faucets at 0.25 gallons/cycle. Section
5.4.1 and Table 1 of ASMEA112.18.1/CSA B125.1-Plumbing Supply Fittings also establish the
maximum flow rates for public lavatory (other than metering) faucets at 0.5 gpm. As a
consequence, this category of faucet is not covered by the current specification. If WaterSense
decides to address water efficiency and performance for these types of faucets, it will do so
under a separate specification at a later time.
Water-Efficiency and Performance Criteria
The water-efficiency component of this specification establishes a maximum flow rate of 1.5
gpm at an inlet pressure of 60 psi. Lowering the maximum flow rate from 2.2 gpm to 1.5 gpm
(both at 60 psi) represents a 32 percent reduction, which is consistent with WaterSense's stated
goal of improving efficiency by at least 20 percent. Even when installed in systems with high
water pressure (up to 80 psi), faucets designed to this specification will have maximum flow
rates of approximately 1.75 gpm, which still represents a greater than 20 percent increase in
efficiency. WaterSense chose to specify a test pressure of 60 psi to maintain consistency with
the current industry standard (ASME A112.18.1-Plumbing Supply Fittings) to which all faucets
sold in the United States must comply.
The requirements of this specification are also in harmony with other international standards.
The Joint Standards Australia/Standards New Zealand Committee established standards for the
rating and labeling of water-efficient products (AS/NZS 6400:2005). As part of the standard,
water-efficient faucets are rated on a scale of 1 to 6 based on maximum flow rates. Under this
system, comparable 1.5 gpm WaterSense labeled lavatory faucets would receive a 5 out of 6
star rating, meeting criteria for maximum flow rates between 4.5 liters per minute (L/min) (1.2
gpm) and 6.0 L/min (1.6 gpm).
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
Meeting or exceeding user expectations via the establishment of performance criteria for
WaterSense labeled products is an important aspect of the WaterSense program. From the
outset of discussions with interested parties, WaterSense was aware that performance of water-
efficient lavatory faucets is affected by low water pressures. To ensure user satisfaction with
WaterSense labeled lavatory faucets or lavatory faucet accessories across a range of possible
user conditions, WaterSense has established a minimum flow rate of 0.8 gpm at 20 psi in the
specification.
In developing these water-efficiency and performance criteria, WaterSense evaluated
comments received during the draft specification's public forum and public comment period (see
Response to Issues Raised During Public Comment on February 2007 Draft Specification for
WaterSenseSM Labeling of High-Efficiency Lavatory Faucets). WaterSense also considered
user satisfaction data generated from four high-efficiency lavatory faucet retrofit studies and the
impact of pressure changes on product flow rates for various types of lavatory faucet
accessories.
WaterSense established a maximum flow rate of 1.5 gpm at 60 psi because interested parties
that provided comments on the draft specification generally agreed that a flow rate of 1.5 gpm
would provide no noticeable difference for most users. In addition, data collected from retrofit
studies demonstrate a high level of user satisfaction with high-efficiency lavatory faucets that
have maximum flow rates of 1.0 and 1.5 gpm. Aquacraft, Inc. conducted retrofit studies in
Seattle, Washington (2000)6 and East Bay Municipal Utility District (EBMUD), California (2003)7
in which they replaced existing lavatory faucet aerators with 1.5 gpm pressure compensating
aerators. In the Seattle study, 58 percent of the participants felt their faucets with the new
aerators performed the same or better than their old faucet fixtures and 50 percent stated they
would recommend these aerators to others. In the EBMUD study, 80 percent of the participants
felt their faucets with the new aerators performed the same or better than their old faucet
fixtures, and 67 percent stated they would recommend these aerators to others. A third
Aquacraft, Inc. retrofit study conducted in Tampa, Florida (2004)8 replaced existing lavatory
faucet aerators with 1.0 gpm pressure compensating aerators. The participants in this study
were receptive to an even higher-efficiency fixture, with 89 percent saying their new aerators
performed the same or better than their old faucet fixtures and would recommend them to
others. Seattle Public Utilities also provided WaterSense with survey results of customer use
and satisfaction with 1.0 gpm pressure compensating aerators distributed through the utility's
direct-mail showerhead and faucet aerator pilot program. According to its survey, 94 percent of
the participants that received the free aerators installed them and only 2 percent disliked the
aerators and removed them.9
6 Seattle Home Water Conservation Study: The Impacts of High-Efficiency Plumbing Fixture Retrofits in
Single-Family Homes, December 2000.
7 Water Conservation Study: Evaluation of High-Efficiency Indoor Plumbing Fixture Retrofits in Single-
Family Homes in the East Bay Municipal Utility District Service Area, July 2003.
8 Tampa Water Department Residential Water Conservation Study: The Impacts of High-Efficiency
Plumbing Fixture Retrofits in Single-Family Homes, January 2004.
9 Seattle Public Utilities. "Showerhead/Aerator Pilot Program Summary." Unpublished.
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
WaterSense established a minimum flow rate of 0.8 gpm at 20 psi for several reasons. First,
WaterSense felt this minimum flow rate was reasonable to ensure user satisfaction in homes
with low water pressure based on comments that were received regarding the draft
specification. Second, WaterSense received comments from several utilities regarding
programs in which 1.0 gpm lavatory faucet aerators are provided to customers. These products
have shown a high level of user satisfaction, and WaterSense wants to recognize these
products and the efforts of the utilities to ensure that additional water savings can be achieved
through such programs. Third, WaterSense wants to avoid restricting design options to the
extent possible. The specification leaves open the possibility for the use of fixed orifice flow
control devices (with a maximum flow rate of 1.5 gpm) instead of restricting manufacturers to
the use of pressure compensating devices. Under the specification, a 1.5 gpm maximum flow
rate fixed orifice aerator could qualify for use of the label (according to currently available
product specifications and flow curves). Pressure compensating devices with maximum flow
rates between 1.5 and 1.0 gpm could also qualify for the use of the WaterSense label
(according to currently available product specifications and flow curves). WaterSense believes
that this approach allows for the greatest degree of design freedom for manufacturers and
supports existing utility programs, while still ensuring a high level of performance and user
satisfaction.
In order for high-efficiency lavatory faucets to effectively emerge in the market following the
release of the final version of this specification, the market must ideally be equipped to produce
the faucets or faucet technology that the specification requires. WaterSense is not currently
aware of any lavatory faucets on the market with a maximum flow rate of 1.5 gpm. There are,
however, several types and models of faucet components and accessories currently available
that have the capability to control the flow to the level that is required by this specification. As a
result, WaterSense is confident that faucets and faucet accessories that meet the requirements
of this specification can be readily brought to market.
Potential Water and Energy Savings
To estimate water and energy savings that can be achieved by products that meet this
specification, WaterSense examined the Seattle (2000) and EBMUD (2003) Aquacraft retrofit
studies, which provided actual water consumption reductions generated by the installation of
high-efficiency, pressure-compensating 1.5 gpm aerators on lavatory faucets. WaterSense
expects the results under this specification to be similar to what was found in these two studies.
These studies indicate that installing high-efficiency aerators can yield significant reductions in
household water consumption. Post faucet retrofit, the weighted average daily per capita
reduction in water consumption achieved was 0.6 gallons per capita per day (gcpd). It is
important to note that in both of these studies, kitchen faucets in each household were
retrofitted with 2.2 gpm pressure compensating aerators. While these retrofits contributed in
part to overall reductions in household water consumption, the retrofits simply brought those
kitchen sink faucets up to current water-efficiency standards, therefore, WaterSense decided to
set aside this confounding influence in order to estimate the water savings. Assuming the
average household consists of 2.6 people, this equates to an average annual household
savings of approximately 570 gallons of water (see Calculation 1).
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
Calculation 1. Average Household Water Savings
0.6 gpcd 2.6 people/household 365 days = 570 gallons annually
Extrapolated to the national level, potential estimated water savings could be as great as 61
billion gallons annually (see Calculation 2). These estimates clearly demonstrate the significant
water savings potential of high-efficiency lavatory faucets and accessories.
Calculation 2. National Water Savings
570 gal/year 107,574,00010 occupied residences w/ plumbing fixtures = 61 billion gallons
Based upon these estimates, the average household could save more than 70 kWh of electricity
(see Calculation 3) or 350 cubic feet of natural gas (see Calculation 4) each year. National
savings could exceed 3 billion kWh hours and 20 billion cubic feet (Bcf) of natural gas each year
(see Calculations 5 and 6).
Calculation 3. Electricity Saving Per Household
(570 gal/year 0.70) (176.5 kWh of electricity/1,000 gal) = 70 kWh of electricity per year
Calculation 4. Natural Gas Savings Per Household
(570 gal/year 0.70) (0.8784 Mcf of natural gas/1,000 gal) = 0.35 Mcf (350 cubic feet) of
natural gas per year
Calculation 5. National Electricity Savings Potential
(61,000,000,000 gal 0.70 0.40) (176.5 kWh of electricity/1,000 gal) = 3 billion kWh of
electricity nationwide
Calculation 6. National Natural Gas Savings Potential
(61,000,000,000 gal 0.70 0.56) (0.8784 Mcf of natural gas/1,000 gal) = 20 million Mcf of
natural gas nationwide = 20 Bcf of natural gas nationwide
These calculations are based upon the following assumptions:
Approximately 70 percent of faucet water used in a household is hot water (Tampa and
Seattle Aquacraft studies).
42,788,000 (approximately 40 percent) of occupied residences in the United States heat
their water using electricity.11
60,222,000 (approximately 56 percent) of occupied residences in the United States heat
their water using natural gas.12
10 U.S. Department of Housing and Urban Development and U.S. Census Bureau. American Housing
Survey for the United States 2005. Table 1A-4 page 5.
11 U.S. Department of Housing and Urban Developmen
Survey for the United States 2005. Table 1A-5, page 6^
12 U.S. Department of Housing and Urban Development
Survey for the United States 2005. Table 1A-5, page 6^
11 U.S. Department of Housing and Urban Development and U.S. Census Bureau. American Housing
i
12 U.S. Department of Housing and Urban Development and U.S. Census Bureau. American Housing
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
Water heating consumes 0.1765 kWh of electricity per gallon of water heated assuming:
o Specific heat of water = 1.0 BTU/lb ฐ F
o 1 gallon of water = 8.34 Ibs
o 1 kWh = 3,412 BTUs
o Incoming water temperature is raised from 55ฐ F to 120ฐ F (A 65 ฐ F).
o Water heating process is 90 percent efficient, electric hot water heater.
Calculation 7.
[(1 gal 1.0 BTU/lbs ฐ F) (1KWh/3,412 BTUs) / (1 gallon/8.34 Ibs) 65ฐ F] / 0.90
= 0.1765kWh/gal
Water heating consumes 0.8784 Mcf of natural gas per 1,000 gallons of water heated
assuming:
o Specific heat of water = 1.0 BTU/lb ฐ F
o 1 gallon of water = 8.34 Ibs
o 1 Therm = 99,976 BTUs
o Incoming water temperature is raised from 55ฐ F to 120ฐ F (A 65 ฐ F)
o Water heating process is 60 percent efficient, natural gas hot water heater
Calculation 8.
[(1 gal 1.0 BTU/lbs ฐ F) (1 Therm/99,976 BTUs) / (1 gallon/8.34 Ibs) 65ฐ F] / 0.60
= 0.009053 Therms/gal
Calculation 9.
0.010428 Therms/gal 1,000 gal 1Mcf/10.307 Therms = 0.8784 Mcf/kgal
Cost Effectiveness and Payback Period
The average homeowner retrofitting their lavatory faucets with WaterSense labeled high-
efficiency lavatory faucet accessories (e.g., aerator, laminar flow device, flow restrictor) will
realize accompanying $3.26 savings on water and wastewater cost annually due to lower water
consumption (see Calculation 10).
Calculation 10. Annual Water and Wastewater Cost Savings
570 gallons/year $5.72/1,000 gallons13 = $3.26/year
Factoring in the accompanying energy savings, the average household with electric water
heating may save an additional $6.65 (70 kWh/year $.095/kWh), for a combined annual
savings of $9.91. The average household with natural gas water heating, may save an
additional $4.56.(0.35 Mcf/year $13.04/Mcf), for a combined annual savings of $7.82.
13 Raftelis Financial Consulting. Water and Wastewater Rate Survey. American Water Works Association.
2004.
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High-Efficiency Lavatory Faucet Specification
Supporting Statement
Assuming that the average household has two lavatory faucets14, replacing the aerators in each
lavatory faucet with a WaterSense labeled aerator would save $1.63 per faucet on annual water
and wastewater costs. The average payback period for the replacement of two lavatory faucet
aerators would be approximately 10 months for those with electric water heating and 12 months
for those heating with natural gas (See Calculations 11 and 12).
Calculation 11. Average Payback Period (Electric Water Heating)
$8.00 / [$3.26/year + (70 kWh/year $.095/kWh)] = 0.8 years (-10 months)
Calculation 12. Average Payback Period (Natural Gas Water Heating)
$8.00 / [$3.26/year + (0.35 Mcf/year $13.04 /Mcf)] = 1.0 years (-12 months)
These calculations are based upon the following assumptions:
WaterSense labeled retrofit devices retail for $4.00 each.
Average cost of electricity is $0.095/kWh15.
Average cost of natural gas is $13.04/Mcf16.
Unit Abbreviations:
Bcf = billion cubic feet
BTU = British thermal unit
F = Fahrenheit
gal = gallon
gpcd = gallons per capita per day
gpm = gallons per minute
kgal = kilogallons
kWh = kilowatt hour
Ibs = pounds
L/min = liters per minute
Mcf = thousand cubic feet
psi = pressure per square inch
WaterSense assumes that the cost of new faucets manufactured and sold as WaterSense
labeled fixtures will not increase significantly since in many cases the manufacturer will simply
need to substitute the current flow regulating device with a similar, more efficient rated device.
In many cases this will be as simple as switching from the current 2.2 gpm aerator or laminar
flow device to a comparable 1.5 gpm WaterSense labeled device
14 U.S. Department of Housing and Urban Development and U.S. Census Bureau. American Housing
Survey for the United States 2005. Table 1A-3 page 4.
15 Average Retail Price of Electricity to Ultimate Customers by End-Use Sector, Energy Information
Administration,
16 Short-Term Energy Outlook, Energy Information Administration,
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