GAO

United States General Accounting Office

Report to Congressional Requesters

August 2000 WATER 

INFRASTRUCTURE

Water-Efficient 

Plumbing Fixtures 

Reduce Water 

Consumption and 

Wastewater Flows

GAO/RCED-00-232 

Page 1 GAO/RCED-00-232 Low-Flow Toilets

Contents

Letter 3

Appendixes Appendix I: Evolution of Required Performance Tests for

Low-Flow Toilets 26

Appendix II: Preexisting State and Local Standards for 

Water-Efficient Plumbing Fixtures and Their Status

If National Standards Were Repealed 29

Appendix III: Summary of Accelerated Toilet Replacement 

Programs in Six Localities 31

Appendix IV: Projected Reduction in Water Consumption by 

2010 and 2020, by Location 32

Appendix V: Projected Investments in Drinking Water Infrastructure

by the Year 2020, by Location 34

Appendix VI: Scope and Methodology 35

Bibliography 38

Tables Table 1: National Water Efficiency Standards 6

Table 2: Water Use by Type of Toilet 10

Table 3: Reported Savings Attributable to Low-Flow Toilets

in Studies Using Precise Measurements 11

Table 4: Evolution of Industry Testing Requirements for Low-Flow 

Toilets 27

Table 5: State and Local Standards for Water-Efficient Plumbing 

Fixtures 29

Figures Figure 1: Mean Daily Residential Water Use at 12 Study Sites 9

Figure 2: Percentage of Water Savings by Location 17

Abbreviations

EPA Environmental Protection Agency

GAO General Accounting Office
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Page 3 GAO/RCED-00-232 Low-Flow Toilets

United States General Accounting Office

Washington, D.C. 20548

Resources, Community, and

Economic Development Division

B-285890 Letr

August 31, 2000

The Honorable Michael Bilirakis

Chairman, Subcommittee on Health and Environment

Committee on Commerce 

House of Representatives

The Honorable Sherwood L. Boehlert

Chairman, Subcommittee on Water Resources

and Environment

Committee on Transportation

and Infrastructure

House of Representatives

Water-efficient plumbing fixtures, such as low-flow toilets and 

showerheads, first became generally available to American consumers in 

the late 1980s. Subsequently, under the Energy Policy Act of 1992, the 

Congress established uniform national standards for the manufacture of 

these fixtures to promote conservation by residential and commercial 

water users. The act also preempted state and local authorities from setting 

different standards. Proposed legislation filed in 1999 would have repealed 

the national standards and eliminated the act’s preemptive language. 

Concerned about the potential implications of the proposed legislation, you 

asked us to examine the impact of the national water efficiency standards. 

Specifically, you asked us to provide information on (1) the estimated 

impact of the national water efficiency standards on water consumption 

levels and wastewater flows and (2) how repealing the national standards 

might affect projected investments in drinking water and wastewater 

treatment infrastructure, state and local governments’ ability to finance 

their infrastructure needs, and the likelihood of moratoria on new 

residential and commercial construction if the demand for water is 

unabated.
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Results in Brief No studies estimating the impact of the national water efficiency standards 

on water consumption or wastewater flows nationwide have been 

completed so far. However, studies designed to measure the impacts of 

using water-efficient plumbing fixtures in specific locations have shown 

that, compared with their less efficient counterparts, low-flow fixtures 

conserve water, particularly in the case of toilets. The best example is a 

comprehensive study of water use in nearly 1,200 homes at 12 study sites 

that determined, among other things, that homes with low-flow toilets used 

about 40 percent less water for flushing than other homes in the study.1

Estimating the impact of the national standards is difficult because some 

use of low-flow fixtures would likely occur for other reasons—that is, even 

in the absence of the standards. These reasons include (1) state and local 

laws that preceded the national standards and (2) incentives, such as 

rebate programs sponsored by local governments, that encourage the 

replacement of less efficient fixtures. Nevertheless, major studies initiated 

by the American Water Works Association and the Environmental 

Protection Agency (EPA) are developing long-term projections of the 

nationwide impact of the water efficiency standards, using precise 

measurements of the water savings per fixture as a starting point and 

taking into consideration expected population growth, the average 

replacement rate for plumbing fixtures, and other data. Preliminary results 

indicate that by 2020, water consumption could be reduced by about 3 to 9 

percent, depending on the location, and wastewater flows to publicly 

owned treatment works could be reduced by an estimated 13 percent 

nationwide by 2016.

Although their precise impact is uncertain, repealing the national standards 

could affect the extent to which reductions in water consumption and 

wastewater flows are achieved and, thus, limit the extent to which local 

communities’ investments in drinking water or wastewater infrastructure 

can be deferred or avoided. For example, an ongoing study estimates that 

for the 16 localities analyzed to date, the standards will cause water 

consumption to be reduced enough to save local water utilities from $165.7 

million to $231.2 million by 2020 because planned investments to expand 

drinking water treatment or storage capacity can be deferred or avoided.2

1

See Residential End Uses of Water, American Water Works Association Research 

Foundation (1999).

2

The dollar amounts presented here represent the present value of the net savings 

discounted at 7 and 3 percent, respectively.
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Location-specific estimates for wastewater treatment facilities indicate 

that reductions in wastewater flows can also lead to significant savings. 

For example, one regional authority estimates savings of $12 million to $14 

million for each million-gallons-per-day reduction in wastewater flows. 

However, the estimates for both drinking water and wastewater 

infrastructure are only as accurate as the predictions that individual 

utilities are able to make about future investment decisions and, for the 

most part, do not account for the fact that some use of water-efficient 

fixtures would continue in the absence of the national standards. Repealing 

the national water efficiency standards could exacerbate the financial 

pressures facing local communities by forcing them to build or expand 

treatment and storage facilities sooner than planned. However, even if the 

standards were repealed, state and local officials told us that imposing 

moratoria on new residential or commercial construction would be 

considered only as a last resort. 

Background The Energy Policy Act of 1992 established water conservation standards 

for the manufacture of four types of plumbing fixtures: toilets, kitchen and 

lavatory faucets, showerheads, and urinals. With limited exceptions, the 

standards apply to all models of the fixtures manufactured after January 1, 

1994.3

 (See table 1.)

3

For example, the maximum allowable water use for certain gravity tank-type toilets labeled 

as “Commercial Use Only” manufactured after January 1, 1994, and before January 1, 1997, 

is 3.5 gallons per flush. Similarly, flushometer valve toilets were not required to meet the 1.6-

gallons-per-flush standard until January 1, 1997. In the case of “blowout toilets,” which use 

pressurized jets of water to flush the bowl’s contents, the maximum allowable water use is 

3.5 gallons per flush.
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Table 1: National Water Efficiency Standards

a

A gravity tank-type toilet is designed to flush by gravity only with water supplied to the 

bowl.

b

A flushometer tank toilet is designed to flush using a flushometer valve, which is attached 

to a pressurized water supply pipe and, when actuated, opens the line for direct water flow 

into the bowl at a rate and predetermined quantity needed to properly operate the toilet.

c

An electromechanical hydraulic toilet is designed to flush using electronically controlled 

devices, such as air compressors, pumps, motors, or macerators in place of or as an aid to 

gravity in flushing the toilet bowl.

d

An aerator is an apparatus for controlling water flow (e.g., from faucets).

Under the Department of Energy’s regulations, water-efficient plumbing 

fixtures must meet the standards for maximum water consumption. For 

each model of a regulated plumbing fixture, manufacturers and private 

labelers must submit a compliance statement to the Department to certify 

that the model complies with the applicable water conservation standard 

and that all required testing has been conducted according to the test 

requirements prescribed in the regulations. In addition, the Department’s 

regulations prohibit manufacturers and private labelers from distributing in 

commerce any fixture that does not meet the water conservation standard 

prescribed under the Energy Policy Act of 1992, and provide for the 

assessment of a civil penalty of not more than $110 per violation. 

The plumbing industry has also established certain performance or 

efficiency standards for water-efficient plumbing fixtures. For example, 

manufacturers must demonstrate that low-flow toilets consume no more 

than 1.6 gallons per flush and can pass a series of tests directed at the 

effectiveness of the toilet’s flushing performance and other factors, and 

each new toilet model must be tested for compliance by an approved 

Fixture type Maximum allowable water use

Toilets, including gravity tank-type toilets,a

flushometer tank toilets,b and 

electromechanical hydraulic toiletsc

1.6 gallons per flush

Kitchen and lavatory faucets (or 

replacement aeratorsd

)

2.5 gallons per minute, when measured at a 

flowing water pressure of 80 pounds per 

square inch

Showerheads 2.5 gallons per minute, when measured at a 

flowing water pressure of 80 pounds per 

square inch

Urinals 1.0 gallon per flush
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laboratory before it reaches the marketplace. Testing protocols for 

demonstrating compliance with these standards are developed by the 

American Society of Mechanical Engineers and approved by the American 

National Standards Institute.

Most of the water consumed for domestic and commercial purposes is 

supplied by public drinking water systems, which account for about 12 

percent of the total fresh water use in the United States, according to a 

recent report by the U.S. Geological Survey.4

 Water used for agricultural 

purposes, including water for irrigation and livestock, accounts for about 

41 percent of total fresh water use, and the water used by thermoelectric 

power plants is about 39 percent of the total. Growing concerns about the 

adequacy of public water supplies to meet increased demands led a number 

of states and localities to impose their own requirements for water-efficient 

plumbing fixtures before the national standards took effect. 

Water-Efficient 

Plumbing Fixtures Are 

Reducing Water 

Consumption Levels 

and Wastewater Flows

Substantial evidence shows that the use of water-efficient plumbing 

fixtures conserves water. A number of localized studies have measured the 

impact of installing water-efficient plumbing fixtures through sophisticated 

sensors, before-and-after comparisons of water bills, or other means. 

Although the results varied, the studies generally concluded that low-flow 

fixtures are effective in saving water. Determining the extent to which the 

use of low-flow fixtures is attributable to the national standards is 

problematic because some use of low-flow fixtures would likely occur for 

other reasons. Two major studies now under way are attempting to 

estimate the standards’ impact on water consumption and wastewater 

flows over the long term.

4

See Estimated Use of Water in the United States in 1995, U.S. Geological Survey Circular 

1200 (1998).
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Studies Using Precise 

Measurements Show That 

Water-Efficient Plumbing 

Fixtures Conserve Water

Although no major studies estimating the nationwide impact of the national 

water efficiency standards have been completed so far, a number of studies 

have been conducted to measure the extent to which water-efficient 

plumbing fixtures conserve water. The most comprehensive study we 

found was funded by the American Water Works Association’s Research 

Foundation, in conjunction with 22 municipalities and water 

organizations.5

 The purpose of the study was to gather empirical evidence 

on variations in water use for plumbing fixtures and other water-using 

appliances within single-family homes.6

 Sophisticated sensors were placed 

on residential water meters at about 100 households in each of the 12 

participating study sites to obtain detailed information on actual water 

use.7

 Figure 1 shows, for the 12 study sites, the distribution of indoor water 

use by type of fixture. According to the study, total mean indoor per-capita 

water use was 69.3 gallons per day, of which, toilets accounted for about 

18.5 gallons per capita per day, or about 27 percent of the total.

5

See Residential End Uses of Water, American Water Works Association Research 

Foundation (1999). The American Water Works Association is a professional organization 

representing individuals from the water supply industry and the drinking water community 

at large.

6

The study involved 12,000 randomly selected customer accounts, or about 1,000 in each of 

12 study sites, and included households with low-flow fixtures, those with less efficient 

fixtures, and those with a mix of low-flow and higher-volume fixtures. Sensors were used to 

record detailed water use data at about 10 percent of the households.

7

The 12 study sites were Boulder, Colorado; Cambridge and Waterloo, Ontario, Canada; 

Denver, Colorado; Eugene, Oregon; Las Virgenes, California; Lompoc, California; Phoenix, 

Arizona; San Diego, California; Scottsdale and Tempe, Arizona; Seattle, Washington; Tampa, 

Florida; and Walnut Valley, California.
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Figure 1: Mean Daily Residential Water Use at 12 Study Sites

Source: Residential End Uses of Water, American Water Works Association Research Foundation 

(1999), p. xxv.

Among other things, the detailed water flow data captured by the sensors 

allowed researchers to compare water consumption in homes equipped 

with low-flow toilets with those using higher-volume models. Significantly, 

the study found that the average number of flushes per day in households 

with low-flow toilets was 5.04—only slightly higher than the average of 4.92 

flushes per day in households with higher-volume toilets.8

 Table 2 

summarizes the results of the analysis. 

0 5 10 15 20

Dishwasher

Bath

Other domestic

Leaks

Faucet

Shower

Clothes washer

Toilet

Gallons per capita per day

1.0

1.2

1.6

9.5

10.9

11.6

15.0

18.5

8

See Residential End Uses of Water, American Water Works Association Research 

Foundation (1999), p. xviii.
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Table 2: Water Use by Type of Toilet

Legend

< means less than

> means greater than

Source: Residential End Uses of Water, American Water Works Association Research Foundation, pp. 

131-132.

In addition to the comprehensive study by the American Water Works 

Association’s Research Foundation, a number of studies have used 

similarly sophisticated equipment to measure water flow to individual 

appliances at a small number of households. The purpose of these studies 

was to estimate whether water-efficient fixtures reduce water consumption 

in residences and if so, by how much. Toilets consume the most water in 

residences, and, as such, they have been the focus of the greatest attention, 

but showerheads, faucets, and clothes washers have also been considered 

in these studies, although the latter will not be subject to national 

standards until 2004.9

 The studies all agree that compared with older 

toilets, ultra-low-flow toilets save significant amounts of water, easily 

overwhelming any changes in user practices (such as the frequency of 

flushing). Table 3 summarizes the results of the studies we examined.

Average water use 

Household 

toilet types

Average gallons

per flush

Number of

households

Gallons per

toilet per day

Gallons per

capita per day

Low-flow only < 2.0 101 24.2 9.6

Mix of low-flow 

and highervolume 

2.0 − 3.5 311 45.4 17.6

Higher-volume 

only

> 4.0 776 47.9 20.1

All households 1,188 45.2 18.5

9

On May 23, 2000, the Department of Energy reached an agreement with appliance 

manufacturers and environmental and energy conservation organizations to phase in water 

and energy efficiency standards for clothes washers beginning in 2004. 
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Table 3: Reported Savings Attributable to Low-Flow Toilets in Studies Using Precise Measurements

a

In this study, half of the toilets were replaced with low-flow toilets and half were not; the 

reported savings were obtained by averaging the results for all toilets—higher-volume and 

low-flow. For the purpose of this table, we computed the water use and the amount of 

savings on the basis of the results for the replaced toilets. 

b

We obtained a copy of the draft report on this study. Because the authors are still finalizing 

the report, we did not have all of the information that would be useful in evaluating the 

results of this study. 

c

Because the study did not explicitly report the average water use before and after retrofit, 

we estimated these values by multiplying the average volume per flush by the number of 

flushes per person. The difference between these values does not equal the amount of 

savings reported in the study, which was measured separately for each toilet before 

averaging and, thus, is more accurate.

Sources:

Boulder: Project Report: Measuring Actual Retrofit Savings and Conservation Effectiveness Using 

Flow Trace Analysis. Prepared for: City of Boulder, Colorado, Utilities Division, Office of Water 

Conservation, by Aquacraft Water Engineering & Management (May 16, 1996).

East Bay: East Bay Municipal Utility District Water Conservation Study. Prepared for: East Bay MUD, 

Oakland, California, A. Aher, et al, Stevens Institute of Technology, Building Technology Laboratory, T. 

P. Konen, Director, Report No. R 219 (Oct. 1991).

Seattle: Draft report prepared for EPA and Seattle Public Utilities, by P. Mayer and W. DeOreo, 

Aquacraft, Inc., private communication from P. Mayer (July 2000).

Tampa: The Impact of Water Conserving Plumbing Fixtures on Residential Water Use Characteristics: 

A Case Study in Tampa, Florida. Prepared for: City of Tampa Water Department, Water Conservation 

Section, by Stevens Institute of Technology and Ayres Associates, T. P. Konen and D. L. Anderson, 

Principal Investigators (Feb. 1993).

While it is widely believed that the installation of water-efficient 

showerheads and sink faucets also results in significant savings, the studies 

we reviewed are not in complete agreement on this point. The East Bay, 

California, study reported savings of 1.7 gallons per capita per day with 

low-flow showerheads—about one-third of the savings resulting from toilet 

replacement. The Tampa, Florida, study reported savings of 3.6 gallons per 

capita per day—(1) more than half of the savings from toilet replacement 

Water use in toilets (gal. per capita per day)

Location

Date

published

Number of

households

Before

retrofit

After

retrofit

Amount

saved

Percentage

saved

Boulder, Colo.a May 1996 14 15.9 7.6 8.3 52

East Bay Municipal 

Utility District, Calif.

Oct. 1991 25 12.8c 6.7c 5.3c 41c

Seattle, Wash.b July 2000

(draft)

37 18.8 8.1 10.6 57

Tampa, Fla. Feb. 1993 25 13.3 7.2 6.1 46
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and (2) just over one-third of the total water used for showers before the 

replacement. On the other hand, the study in Boulder, Colorado, which also 

used the most advanced equipment, found that showerhead replacement 

had no statistically significant effect on shower water consumption. The 

authors of this study called for further research, knowing that this result 

was anomalous compared with other, similar studies. 

For clothes washers, the largest user of water in households after toilets, 

two studies examined the savings associated with using water-efficient 

appliances: one in Boulder, Colorado, and one in Seattle, Washington. In 

Boulder, only 4 of the 14 homes involved in the study had water-efficient 

washers installed for the test period—2 homes used one model of washer, 

and 2 homes used another model. In the test homes, the study found an 

average reduction of 61 percent in water use for clothes-washing—from 

17.9 to 7.0 gallons per capita per day. One of the models tested reduced 

water consumption for clothes-washing by 39 percent on average, and the 

other produced a 76-percent reduction. A variety of clothes washers were 

tested in the Seattle study, and the results showed a savings of 5.4 gallons 

per capita per day, or a reduction of about 37 percent from the baseline 

water use. 

Although the studies discussed here all indicate that low-flow toilets and 

other water-efficient fixtures save significant amounts of water, evidence 

suggests that the savings could be even greater if performance across all 

models of the fixtures were more consistent. In the case of toilets,10 the 

technology has improved over time, according to water industry 

representatives, manufacturers, plumbing contractors, and an official with 

the American Society of Mechanical Engineers. They told us that when the 

national standards first took effect, existing toilet models were modified so 

that they used less water, but until the basic design was changed to 

accommodate the lower water flow, some models did not perform 

effectively. Today, there is wide agreement that the technology is much 

better than in the past; however, some of the officials we interviewed, 

including plumbing contractors and water industry representatives, believe 

that the performance tests required under the industry standards for lowflow toilets are too easy to pass and, as a result, some poorly performing 

models still reach the market. (See app. I for additional information on the 

10For the purpose of this report, we focused on low-flow toilets—the fixtures that (1) have 

the greatest potential for water savings and (2) have been subject to the most complaints 

regarding their performance. 
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Page 13 GAO/RCED-00-232 Low-Flow Toilets

required performance tests for low-flow toilets and how the requirements 

have evolved over time.)

Ongoing National Studies 

Suggest That National Water 

Efficiency Standards Will 

Continue to Reduce Water 

Consumption and 

Wastewater Flows in the 

Long Term

Estimating the impact of the national standards is difficult because some 

use of low-flow fixtures would likely occur for other reasons—that is, even 

in the absence of the standards. Nevertheless, major studies initiated by the 

American Water Works Association and EPA are developing long-term 

projections of the nationwide impact of the water efficiency standards, 

using precise measurements of the water savings per fixture as a starting 

point and taking into consideration expected population growth, the 

average replacement rate for plumbing fixtures, and other data. 

Preliminary results indicate that over the long term, reductions in water 

consumption and wastewater flows could be substantial.

Estimating the National 

Standards’ Impact Is Difficult 

Because Some Use of WaterEfficient Fixtures Would Likely 

Occur Even Without the 

Standards

The studies by both the American Water Works Association and EPA are 

attempting to quantify the effect of the national water efficiency standards 

for plumbing fixtures. In both cases, the estimate of future savings depends 

in part on assumptions about the baseline—that is, the extent to which the 

use of low-flow fixtures would occur for reasons other than the national 

standards. We identified the following circumstances in which the use of 

water-efficient plumbing fixtures had occurred prior to the standards, as 

well as factors suggesting that their use is likely to continue whether or not 

the national standards are in effect:
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• State and local standards that preceded the national standards. Sixteen 

states and 6 localities had water efficiency standards for at least two of 

the plumbing fixtures regulated under the Energy Policy Act before the 

national standards took effect in 1994. As of 1999, about 50 percent of 

the nation’s population resided in these locations. All of the states and 

localities had standards for low-flow toilets that, with one exception, 

were consistent with the current national standard. State and local 

standards for showerheads, faucets, and urinals varied from the national 

standard more frequently. Officials from all 16 states and 2 of the 6 

localities with preexisting standards believe that their standards would 

automatically revive if the national standards were repealed.11 (See app. 

II for detailed information on state and local water efficiency 

standards.)

11As a general principle, state and local regulations or ordinances “revive” (i.e., are 

automatically reinstated) under these circumstances. However, this principle may be 

applied differently or not at all, depending on the law of a particular state. State officials in 

Texas and city officials in Phoenix, Arizona, expressed concern that their state legislatures 

might resume previous attempts to repeal their state standards if the national standards 

were no longer in place.
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• Incentives, such as rebates, to encourage the installation of low-flow 

fixtures. We identified at least 36 localities in 12 states that have 

sponsored rebate or free replacement programs, mostly in states and/or 

localities whose own standards for water-efficient plumbing fixtures 

preceded the national standards. Under these programs, the community 

offers some type of financial incentive to encourage people to replace 

their toilets or other plumbing fixtures with more efficient models 

sooner than they would have otherwise. We selected six localities—

Austin, Texas; Los Angeles, California; New York, New York; Phoenix, 

Arizona, and Tampa and Hillsborough County, Florida—to collect 

information about their rebate programs, all of which began before or 

during 1994.12 We found that over 2.3 million low-flow toilets have been 

installed under the six rebate programs, thereby saving more than 100 

million gallons of water per day. With the exception of New York City, all 

of these communities continue to offer rebates, and, according to a city 

official, New York is considering a second rebate program. (See app. III 

for a summary of the accelerated toilet replacement programs in the six 

localities.)

• Manufacturers’ desire for consistency. According to an official with the 

Plumbing Manufacturers’ Institute and industry representatives, 

manufacturers would be reluctant to return to making higher-volume 

plumbing fixtures because of (1) the high cost of retooling and (2) the 

ease of complying with a single national standard rather than a 

hodgepodge of requirements across the country.

• Local ordinances requiring low-flow fixtures. For example, we found a 

few instances of local “retrofit on resale” ordinances in California, two 

of which were adopted before the national standards took effect.13

Typically, these ordinances require that for any residential or 

commercial property offered for sale, the owner must certify that the 

property has been totally retrofitted with low-flow toilets and other 

efficient plumbing fixtures. According to an official with the California 

12The criteria used to select these locations included (1) water efficiency standards that 

preceded the national standards, (2) the use of rebate and/or retrofit programs to accelerate 

the installation of low-flow toilets and other water-efficient fixtures, and (3) an assessment 

of the programs’ impact on water consumption.

13Communities in California currently using “retrofit on resale” programs include the 

Cambria Community Services District, Los Angeles, the North Marin Water District, San 

Diego, San Francisco, and Santa Monica.
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Urban Water Conservation Council, this requirement is currently being 

considered for statewide application because of the state’s severe water 

shortage. 

American Water Works 

Association Is Studying Impact 

on Water Consumption

In January 2000, the American Water Works Association commissioned a 

study to estimate the long-term impact of the national water efficiency 

standards on water consumption from public water systems. To obtain a 

national picture of the standards’ impact, surveys were sent to over 3,700 

drinking water utilities across the United States; as of June 21, 2000, over 

650 utilities had responded. The Association’s contractor is analyzing the 

responses and entering this information into a model developed to estimate 

future water demand with and without the national standards. The 

estimated completion date for the study is September 30, 2000. As shown in 

figure 2, preliminary projections for 16 utilities, which currently serve 

nearly 11 million people, indicate that given expected population growth, 

water consumption will be reduced by 3.3 to 9.1 percent by 2020 as a result 

of the national standards. (See app. IV for a table of the projected water 

savings by 2010 and 2020, by location.)
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Figure 2: Percentage of Water Savings by Location

Legends

WSSC=Washington Suburban Sanitary Commission

Source: Analysis conducted by Maddaus Water Management for the American Water Works 

Association.

The American Water Works Association’s study attempts to estimate the 

savings associated with water-efficient plumbing fixtures by using locationspecific data on projected population growth, projected water demand, and 

the age of the existing housing stock. With the information on existing 

housing stock, the study makes assumptions about the percentage of 

households that already have low-flow fixtures (e.g., homes constructed 

after January 1, 1994, should be completely fitted with efficient fixtures) 

and the rate at which older, higher-volume fixtures will be replaced with 

low-flow models. The accuracy of these assumptions could have a 

significant effect on the validity of the projected reduction in water 

consumption. For example, the study uses a relatively conservative 

assumption regarding the replacement rate for toilets—3 percent per year 

Percent

0

1

2

3

4

5

6

7

8

9

10

Austin, Tex.

Boston, Mass.

Cary, N.C.

Clarksburg, W.Va.

Forth Worth, Tex.

Laurel, Md. (WSSC)

Los Angeles, Calif.

Michigan City, Ind.

Oceanside, Calif.

Phoenix, Ariz.

Pinellas County, Fla.

Rockford, Ill.

Syracuse, N.Y.

Tacoma, Wash.

Tampa, Fla.

4.0

6.8

3.8

6.7

6.2

9.1

3.4

5.5

2.0

3.3 3.2

5.4

3.3

5.8

3.3

5.5

2.4

3.9

2.9

4.7 4.5

7.9

4.5

6.4

2.7

4.9

2.6

3.8

3.1

5.4

2010

2020

Wausau, Wis.

3.2

5.6
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compared with the plumbing industry’s estimates of 4 to 5 percent per year. 

Using a higher replacement rate would increase the savings attributable to 

water-efficient fixtures by 2020.

As noted above, one difficulty in estimating the impact of the standards is 

determining a baseline against which projected water savings are derived, 

taking into account the savings that might occur without the national 

standards. In estimating water consumption without the national 

standards, the model used by the Association’s contractor assumes that 

about 30 percent of the toilets installed in the future would be low-flow 

models (1.6 gal. per flush) and that the remaining 70 percent would use 4.6 

gallons per flush. If the factors noted above resulted in a greater-than-30-

percent proportion of low-flow fixtures, even in the absence of the national 

standards, then the actual savings attributable to the standards would be 

less than that estimated by the Association.

EPA Is Studying Impact on 

Wastewater Flows

While the American Water Works Association focused on water 

consumption from drinking water facilities, EPA is sponsoring a major 

study to estimate the long-term impact of the national water efficiency 

standards on the level of wastewater flows into treatment plants. The 

model used to predict the standards’ impact on wastewater flows 

incorporates information from a variety of sources, including plumbing 

manufacturers, U.S. Census Statistical Abstracts, water utility case studies, 

Consumer Reports, the American Water Works Association Research 

Foundation, and other sources. Preliminary results from this study indicate 

that wastewater flows to publicly owned treatment works will be reduced 

by about 13 percent by 2016.14

As in the American Water Works Association study, the reasonableness of 

key assumptions in EPA’s study could have a significant effect on the 

14In May, we reported that the estimated reduction in wastewater flows by 2020 was about 

25 percent, according to the preliminary results of an EPA-sponsored study. (See Water 

Infrastructure: Impact of National Water Efficiency Standards, GAO/RCED-00-161R, May 1, 

2000.) At that time, to compute the percent reduction in wastewater flows, we used data on 

total U.S. flows at publicly owned treatment works from EPA’s 1996 Clean Water Needs 

Survey Report to the Congress, table C-3, the most recent data available. Since then, EPA 

has provided a better approximation of future wastewater flows, and the agency’s estimate 

of the projected reduction in wastewater flows has been revised with more conservative 

assumptions. In addition, the availability of yearly projections of the reductions in 

wastewater flows from the agency’s contractor allowed us to use data for 2016, consistent 

with the time period for EPA’s estimate of wastewater flows to publicly owned treatment 

works.
B-285890

Page 19 GAO/RCED-00-232 Low-Flow Toilets

validity of results. Most significantly, EPA’s study attributes all savings from 

water-efficient plumbing fixtures to the national standards and does not 

attempt to estimate the reduction in wastewater flows that would have 

occurred in the absence of the standards. Consequently, the estimated 

savings are likely overstated.

Furthermore, according to the agency’s contractor, few historical data are 

available to validate the model’s projections, but the model uses relatively 

conservative assumptions that are periodically cross-referenced against 

data from industry and other sources. At the time of our review, the extent 

of the risk analysis, which is done to determine how sensitive the long-term 

projections are to plausible variations in the values assigned to key 

variables, was limited to replacement rates for the plumbing fixtures. For 

example, the contractor computed a low estimate of long-term water 

savings using a 2-percent replacement rate for residential toilets and a high 

estimate using a 7-percent replacement rate.

Repealing the National 

Water Efficiency 

Standards Will Affect 

the Timing and Cost of 

Infrastructure 

Investments

By reducing water consumption and wastewater flows, the use of waterefficient plumbing fixtures may allow local communities to save money by 

deferring or even avoiding investments in water or wastewater 

infrastructure. Case studies of specific localities suggest that the 

nationwide savings in infrastructure investments could potentially be in the 

billions of dollars. Repealing the national standards could force local 

communities to expand the capacity of their drinking water or wastewater 

treatment facilities sooner than they would otherwise, presenting problems 

for those already hard-pressed to handle the cost of upgrading or replacing 

existing facilities. Determining the precise impact of repeal is problematic 

because, as noted above, the installation of water-efficient plumbing 

fixtures—and the associated water savings—will continue to some extent 

in the absence of national standards. Although many communities are 

concerned about the scarcity of water resources, they would probably 

pursue other alternatives before considering moratoria on new 

construction, according to the states and localities we contacted.
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Page 20 GAO/RCED-00-232 Low-Flow Toilets

National Studies Show 

Potential Savings as a Result 

of Deferring or Avoiding 

Some Infrastructure 

Investments

Preliminary results from the ongoing study sponsored by the American 

Water Works Association indicate that the ability to avoid or defer planned 

investments in drinking water infrastructure as a result of reduced water 

consumption could save local communities millions of dollars. For the 16 

utilities included in the study so far, the total savings associated with 

deferred or avoided infrastructure are estimated to range from $165.7 

million to $231.2 million by 2020, depending on whether the projected 

savings are discounted at 3 or 7 percent, respectively. The projected 

savings amount to approximately 3.6 percent of the total project costs 

without the national water efficiency standards in place.15

The savings estimated for individual localities vary widely on the basis of 

their size, the projected water demand, and the timing and cost of planned 

investments in expanded treatment or storage capacity over the next 20 

years. (See app. V for a table that shows projected infrastructure 

investments with and without the national water efficiency standards and 

the present value of the estimated savings, by location.)

While the estimated savings associated with a community’s ability to defer 

or avoid investments appear to be substantial, the American Water Works 

Association’s contractor acknowledged that the estimates are only as 

accurate as the predictions that individual utilities are able to make about 

future investment decisions. He told us that some utilities simply have not 

prepared detailed demand forecasts or projected their long-term 

infrastructure needs. He believes that other utilities may have provided 

information on their total infrastructure needs—including the investments 

needed to comply with Safe Drinking Water Act requirements or to replace 

or upgrade existing facilities—and did not isolate the investments related 

to expanded capacity. In addition, to the extent that the analysis does not 

account for the fact that some use of water-efficient fixtures would 

continue in the absence of the national standards, the estimated savings are 

likely overstated.

As part of its ongoing study of the impact of the national water efficiency 

standards on wastewater flows, EPA intended to develop a national 

estimate of how reduced wastewater flows might affect planned 

investments in wastewater treatment infrastructure, using its database on 

projected wastewater treatment needs. However, the database does not 

15Project costs include the cost of capital investments, energy, and treatment chemicals.
B-285890

Page 21 GAO/RCED-00-232 Low-Flow Toilets

adequately distinguish between planned investments in expanded capacity 

and those for replacing or upgrading existing capacity. In addition, the 

database does not provide enough detail on the cost of individual treatment 

processes or the timing of planned infrastructure investments. Finally, the 

wide variation in the size and configuration of local wastewater treatment 

facilities makes developing a national estimate problematic.

As an alternative to developing a national estimate, EPA’s contractor is 

using a case study approach and collecting information on the impacts of 

reduced wastewater flows on planned infrastructure investments in 

specific localities. Several cases have been developed to date, but it is 

difficult to isolate the impacts of using water-efficient plumbing fixtures 

from other conservation measures adopted by the localities, as shown in 

the following examples:

• The average dry weather flows at New York City’s 14 wastewater 

treatment plants have dropped about 17 percent from fiscal year 1994 to 

fiscal 1999, and plans to expand the capacity of at least 4 of the plants 

have been halted. The cost of expanding one plant alone was estimated 

to be as high as $1.2 billion. However, aggressive conservation efforts—

including an accelerated toilet replacement program, leak detection and 

repair, large-user audits, and other measures—made this and other 

investments unnecessary.

• After a 1995 study projected that existing wastewater treatment 

capacity would be exceeded by 2001, a regional wastewater treatment 

authority in Washington State used several approaches to reduce 

wastewater flows, including the reduction of infiltration and inflow,16

rebates for low-flow toilets and clothes washers, toilet leak reduction, 

public education, and submetering.17 The authority estimates that it will 

save about $12 million to $14 million for every 1 million gallons per day 

of capacity expansion it can avoid. 

16Infiltration occurs when water gets into the system as a result of groundwater that seeps 

into damaged sewer lines. Inflow is water that enters the system through stormwater drains.

17Submetering is metering for units that are a part of a larger service connection, such as 

apartments in a multifamily building.
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Page 22 GAO/RCED-00-232 Low-Flow Toilets

Repealing the National 

Standards May Increase 

Financial Burden on Local 

Communities

According to EPA’s infrastructure needs surveys for drinking water and 

wastewater treatment, local communities are faced with potentially huge 

investments to expand or upgrade their facilities.18 In 1997, EPA reported to 

the Congress that the total projected needs for all categories of activities 

eligible for funding under the clean water state revolving fund were $139.5 

billion over the next 20 years, including $44.0 billion just for secondary and 

advanced wastewater treatment.19 Similarly, EPA reported in 1997 that the 

nation’s 55,000 community drinking water systems must invest a minimum 

of $138.4 billion over the next 20 years to install, upgrade, or replace 

infrastructure.20 About $48 billion of the estimated needs is for drinking 

water treatment and storage facilities. 

More recently, the Water Infrastructure Network, an affiliation of various 

utility, government, and public works associations, sponsored its own 

study of water and wastewater infrastructure needs.21 The final report 

concluded that the total needs—including capital investments, the cost of 

financing, and annual facility operation and maintenance costs—will 

approach $2 trillion over the next 20 years. The report also states that in 

terms of capital investments, the gap between what local communities are 

currently spending and the amount needed to build, replace, and 

rehabilitate new and existing water and wastewater systems is an 

estimated $23 billion per year, of which $11 billion is needed for drinking 

water systems and $12 billion is needed for wastewater systems. 

To the extent that using water-efficient plumbing fixtures allows 

communities to defer or even avoid investments in drinking water and 

wastewater treatment infrastructure, repealing the national standards 

18Officials from EPA’s Office of Ground Water and Drinking Water and Office of Wastewater 

Management told us that with the exception of the needs reported by a few larger utilities, 

the needs estimates do not factor in the impact of using water-efficient plumbing fixtures on 

projected capacity needs. The Office of Wastewater Management is revising its reporting 

instructions for its next needs survey so that the estimates submitted by local wastewater 

utilities will consider the impact of the standards in the future. Similarly, according to one 

official, the Office of Ground Water and Drinking Water will consider revising its reporting 

instructions for future surveys.

19See 1996 Clean Water Needs Survey Report to Congress, U.S. Environmental Protection 

Agency (1997). 

20See Drinking Water Infrastructure Needs Survey: First Report to Congress, U.S. 

Environmental Protection Agency (Jan. 1997).

21See Clean & Safe Water for the 21st Century, Water Infrastructure Network (2000).
B-285890

Page 23 GAO/RCED-00-232 Low-Flow Toilets

could force local communities to make these investments sooner than 

anticipated. It is difficult to predict the precise impact that such a repeal 

would have on local communities because some conservation efforts will 

continue, regardless. 

During our interviews with officials from states and localities whose water 

efficiency standards preceded the national requirements, we asked about 

their ability to finance the additional infrastructure that might be needed if 

the national standards were repealed. Several of these officials told us that 

obtaining the funds to finance the costs for additional drinking water and 

wastewater treatment infrastructure is difficult, primarily because the 

burden usually falls on individual consumers. While the states have 

revolving loan funds for financing drinking water and wastewater 

treatment infrastructure, this money goes only so far. For example, 

Massachusetts received about $660 million in loan applications from local 

communities last year to finance improvements in drinking water facilities, 

of which, the state was able to fund only $127 million—about 19 percent of 

the total requested. 

If financing is not available from the revolving loan funds or other federal 

sources,22 local communities must rely on other methods for funding 

infrastructure, including issuing bonds and/or increasing taxes. According 

to several of the officials we interviewed, obtaining approval for these 

funding methods is difficult because of public resistance to higher fees or 

taxes. 

Without National Standards, 

Communities Would 

Consider Other Alternatives 

Before Imposing 

Constraints on New 

Construction 

We conducted semistructured interviews with officials from the 16 states 

and 4 of the 6 localities that had adopted their own water efficiency 

standards about the likelihood that local communities would impose 

building moratoria or other constraints on new construction if the national 

standards were repealed. According to several of the officials we 

contacted, building moratoria are rarely imposed. Only 7 of the 16 states 

indicated that moratoria have been used as a result of water shortages, 

usually by only 1 or 2 communities within the state. 

22Other sources of federal financial assistance for water and wastewater infrastructure 

include the U.S. Department of Agriculture’s Water and Waste Disposal program and the 

Department of Housing and Urban Development’s Community Development Block Grant 

program.
B-285890

Page 24 GAO/RCED-00-232 Low-Flow Toilets

Officials from the four localities we contacted indicated that they would be 

extremely reluctant to impose moratoria on new construction and that 

such measures would be used only as a last resort. For example, local 

water officials in Tampa and Hillsborough County, Florida, told us that they 

have never imposed a moratorium on new construction because doing so 

would be devastating to the region’s economic growth. An official from the 

Southwest Florida Water Management District, the regulatory agency 

responsible for managing the water resources in a 16-county area, 

including Tampa and Hillsborough County, said that constraints on new 

construction are politically infeasible.

State officials told us that localities are using or considering other methods 

to deal with current or anticipated water shortages—methods that increase 

water conservation or develop new sources of supply. Officials from 

Georgia, Oregon, and Utah said that local communities within their state 

have modified or would consider modifying their water rates to encourage 

water conservation. In these instances, instead of offering volume 

discounts, the local water system changes its rate structure so that the 

rates increase as water use increases. Officials from Dade and Hillsborough 

Counties in Florida; Tampa, Florida; and Denver, Colorado, told us that 

they have adopted this inverted rate structure. 

Some localities are taking steps to supplement their water supply. One 

alternative is the use of “reclaimed water,” which is wastewater that is 

treated and reused as a nonpotable water source. Hillsborough County is 

already using reclaimed water for lawn watering, and Tampa is planning to 

implement a reclaimed water project in 2001. Desalination of seawater is 

another option. Tampa Bay Water, which supplies water to public utilities 

in Hillsborough County and the city of Tampa as well as other abutting 

counties, is building a desalination plant, which will provide 25 million 

gallons of water per day by the end of 2002.

Agency Comments We provided EPA with a draft of this report for review and comment. 

Officials within EPA’s Office of Water, including the Acting Chief of the 

Protection Branch from the Office of Ground Water and Drinking Water 

and the Director of the Office of Wastewater Management, generally agreed 

with the facts presented in the report. However, the Office of Wastewater 

Management provided a revised estimate of total wastewater flows to 

publicly owned treatment plants in 2016 and a new determination of the 

projected reduction in wastewater flows that would be attributable to the 

population served by such facilities. We incorporated this change into our 
B-285890

Page 25 GAO/RCED-00-232 Low-Flow Toilets

report. In addition, EPA officials suggested a number of technical 

corrections and clarifications, which we incorporated as appropriate.

The scope and methodology we used for our work are discussed in 

appendix VI. We performed our work from January through August 2000 in 

accordance with generally accepted government auditing standards. 

As arranged with your offices, unless you announce its contents earlier, we 

plan no further distribution of this report until 30 days after the date of this 

letter. At that time, we will make copies available to interested 

congressional committees; the Honorable Carol M. Browner, 

Administrator, Environmental Protection Agency; and the Honorable Jacob 

J. Lew, Director, Office of Management and Budget. We will make copies 

available to others on request.

If you have any questions regarding this report, please contact me at (202) 

512-6111. Key contributors to this assignment were Willie Bailey, Charles 

Bausell, Ellen Crocker, Richard Frankel, Ingrid Jaeger, and Robert Sayers.

Peter F. Guerrero

Director, Environmental

Protection Issue
Page 26 GAO/RCED-00-232 Low-Flow Toilets

Appendix I

Evolution of Required Performance Tests for Apendxies

Low-Flow Toilets ApendxiI

Despite technological improvements, performance among low-flow toilets 

can still vary widely in terms of the amount of water used and flushing 

capability, according to a number of sources. Some of the officials we 

interviewed, including plumbing contractors and water industry 

representatives, believe that the performance tests required under the 

industry standards for low-flow toilets are too easy to pass and, as a result, 

some poorly performing models reach the market. One concern about 

current testing procedures is that they do not include an effective 

performance test that addresses the extent to which a toilet is subject to 

clogging—a problem that can contribute to higher-than-expected water 

use. The customer satisfaction surveys we reviewed also indicated that in 

key aspects of performance, such as clogging and the need for double 

flushing, the effectiveness of low-flow toilets can vary significantly, 

depending on the model.1

 Officials from the Plumbing Manufacturers 

Institute agree that industry standards are an important factor in ensuring 

that the performance of low-flow toilets is consistently good across the 

industry. However, they also point to improper installation as a major 

reason why low-flow toilets may exceed 1.6 gallons per flush or otherwise 

perform poorly in the field.

Over the past 10 years, manufacturers have been working to strengthen the 

testing requirements for low-flow toilets, but industry representatives 

acknowledge that it has taken a long time to reach agreement on new tests 

that would address the toilets’ flushing capability. When the industry 

standards for low-flow toilets were updated in 1990, an existing test for 

clogging was eliminated, according to an official with the American Society 

of Mechanical Engineers. Although such a test was considered and 

rejected when the standards were updated in 1995, the standards are 

currently undergoing another revision, and the Society’s project team has 

reached agreement with manufacturers to add a test for clogging.2

 The 

proposed revision must be approved by the Society to become an American 

National Standard; a vote is expected in August 2000. Table 4 shows how 

the testing requirements have changed over the past 10 years.

1

We reviewed several surveys of participants in accelerated toilet replacement programs; 

generally, the participants were asked to rate the performance of their low-flow toilet in 

specific areas and compare it with the higher-volume toilet it replaced. 

2

Under this test, known as a mixed media test, a combination of sponges and paper balls 

must be discharged from the toilet bowl in a prescribed number of flushes.
Appendix I

Evolution of Required Performance Tests for 

Low-Flow Toilets

Page 27 GAO/RCED-00-232 Low-Flow Toilets

Table 4: Evolution of Industry Testing Requirements for Low-Flow Toilets

Legend

N/A = not applicable

Test name Test description 1990 edition 1995 edition Pending revision, 2000a

Water consumption 

per flush

To determine average water consumption: 

average consumption shall not exceed 1.6 

gallons.

New Same Same 

Maximum water 

consumption per 

flush

To determine maximum water consumption after 

adjusting trim components for maximum water 

use: average water consumption shall not 

exceed 2.4 gallons.

N/A N/A New

Ball test To determine solids removal: 100 polypropylene 

balls are placed in toilet bowl; 75 must be 

removed in initial flush.

Same Same Deleted; combined with 

granule test

Granule test To determine solids removal: 2,500 

polyethylene disc-shaped pellets are placed in 

toilet bowl; not more than 125 may remain after 

initial flush.

Same Same Adds 100 nylon balls; not 

more than 3 are allowed 

to remain after initial flush

Ink line test To determine rim washing: a water soluble ink is 

marked on a bowl’s surface; after initial flush, no 

line segment can exceed 1⁄2 inch, and aggregate 

of all segments may not exceed 2 inches.

Same Same A second line is added 2 

inches below rim jets; this 

line is completely washed 

away

Dye test To determine water exchange: a dye is added to 

bowl; 100 percent dilution must occur after initial 

flush.

Same Same Deleted

Trap seal test To determine if trap seal works properly: fixture 

must return to full trap seal after each flush.

Same Same Same

Mixed media test To determine solids removal: 12 sponges and 

10 paper balls are used; not more than 4 

sponges or balls may remain after initial flush.

N/A N/A New

Drain line carry test To determine length of transport of solid wastes: 

fixture must carry waste a minimum of 40 feet in 

the drain line.

New Same Same

Overflow test To determine leakage of gravity tank-type toilets: 

tank fill valve is opened to maximum flow for 5 

minutes; fixture shall not leak.

N/A N/A New

Water rise test To determine wetting of person sitting on seat 

during flush: a vertically positioned rod is 

placed 3 inches under the bowl rim; during flush, 

water should not touch rod.

New Same Deleted

Rim top and seat 

fouling test

To determine soiling of rim top and seat: a plate 

is placed over toilet bowl; no water shall splash 

on plate during flushing.

N/A New Deleted
Appendix I

Evolution of Required Performance Tests for 

Low-Flow Toilets

Page 28 GAO/RCED-00-232 Low-Flow Toilets

a

The pending changes to the performance tests for low-flow toilets are being proposed by 

the American Society of Mechanical Engineers (ASME). The changes will be up for 

approval as a national standard at the August 2000 meeting of the Society.

Sources: Hydraulic Performance Requirements for Water Closets and Urinals, The American Society 

of Mechanical Engineers, An American National Standard. ASME A112.19.6. (1990, 1995) and 

Vitreous China Plumbing Fixtures and Hydraulic Requirements for Water Closets and Urinals, The 

American Society of Mechanical Engineers, ASME A112.19.2 −2000 (May 2000 draft).
Page 29 GAO/RCED-00-232 Low-Flow Toilets

Appendix II

Preexisting State and Local Standards for 

Water-Efficient Plumbing Fixtures and Their 

Status If National Standards Were Repealed ApendxiI

Sixteen states and 6 localities had water efficiency standards for at least 

two of the plumbing fixtures regulated under the Energy Policy Act before 

the national standards took effect in 1994. Table 5 compares the standards 

adopted by each jurisdiction with the national standards.

Table 5: State and Local Standards for Water-Efficient Plumbing Fixtures

Water-efficiency standard

State/locality Effective datea

Ultra-low-flow

toilets (gal. per

flush)

Low-flow

showerhead

(gal. per

minute)

Kitchen faucets

(gal. per min.)

Lavatory

faucets (gal.

per min.)

Urinals

(gal. per

flush)

National standard Jan. 1, 1994 1.6 2.50 2.5 2.5 1.0

States

 Arizona Jan. 1, 1993 1.6 2.50 2.5 2.0 None

 California Jan. 1, 1992 1.6 2.50 2.5 None 1.0

 Connecticutb Jan. 1, 1990 1.6 2.50 2.5 2.5 1.0

 Delaware Apr. 1, 1992 1.6 2.50 2.5 2.0 1.0

 Georgia Apr. 1, 1992 1.6 2.50 2.5 2.0 1.0

 Maryland Apr. 1, 1992 1.6 2.50 2.5 2.0 1.0

 Massachusetts Mar. 2, 1989 1.6 3.00 None None 1.0

 Nevada Mar. 1, 1993 1.6 2.50 2.5 2.5 1.0

 New Jerseyb July 1, 1991 1.6 3.00 3.0 3.0 1.5

 New Yorkb Jan. 1, 1992 1.6 3.00 None 2.0 1.0

 North Carolinab Jan. 1, 1993 1.6 3.00 3.0 3.0 1.5

 Oregon July 1, 1993 1.6 2.50 2.5 2.5 1.0

 Rhode Islandb Mar. 1, 1991 1.6 2.50 2.0 2.0 1.0

Texas Jan. 1, 1992 1.6 2.75 2.2 2.2 1.0

Utah July 1, 1992 1.6 2.50 None None None

Washington July 1, 1993 1.6 2.50 2.5 2.5 1.0

Localities

 Dade County, Fla. Jan. 1, 1992 1.6 2.50 2.5 2.0 1.0

 Denver, Colo. Mar. 1, 1992 1.6 2.50 2.2 2.2 1.0

 District of Columbia Jan. 1, 1992 1.6 2.50 2.5 2.0 1.0

 Hillsborough County, Fla. Mar. 26, 1992 1.6 2.50 2.2 2.2 1.0

Palm Beach, Fla.b Apr. 1, 1991 1.6 3.00 None None 1.5

Tampa, Fla.b June 1, 1990 2.0 2.50 2.0 2.0 1.0
Appendix II

Preexisting State and Local Standards for 

Water-Efficient Plumbing Fixtures and Their 

Status If National Standards Were Repealed

Page 30 GAO/RCED-00-232 Low-Flow Toilets

a

The effective date for the national standards applies to all models of the fixtures, with 

limited exceptions, manufactured after January 1, 1994. For the state and local standards, 

the effective date applies to the standards for ultra-low-flow toilets. Four states had 

different effective dates on standards for other plumbing fixtures. For example, 

Massachusetts’ effective date for toilets was March 2, 1989, and August 9, 1996, for 

showerheads.

b

After the passage of the Energy Policy Act of 1992, state laws and/or local standards were 

revised to comply with national standards.

Sources: For each state, data were obtained from telephone interviews of state or local water officials. 

For all localities except the District of Columbia, data were obtained from local water officials. Data for 

the District of Columbia were obtained from Ranton, Judith L., Water Efficient Plumbing Fixture 

Legislation, A Poll of States With Legislation Adopted, City of Portland, Oreg., Bureau of Water Works 

(May 1992). 

When the Energy Policy Act of 1992 established the national standards, it 

also preempted state and local authorities from setting differing standards. 

We conducted semistructured interviews with officials from the 16 states 

and 4 of the 6 localities with preexisting standards to obtain their views on 

the likely status of their standards if the national standards were repealed. 

All of the state officials we contacted believe that their standards would 

automatically revive. At the local level, officials from two localities told us 

that their local plumbing codes had been modified to incorporate the 

national standards. If the national standards were repealed, local officials 

told us that they would have to take some affirmative action to reinstate 

water efficiency standards at the local level. The other two localities never 

amended their local plumbing codes and thus, officials believe that their 

standards would revive upon repeal of the national standards. 

Both state and local officials told us that if the national standards were 

repealed, enforcement of their standards would become a major problem, 

particularly for localities. According to several of these officials, although 

the national standards regulate the manufacture of water-efficient 

plumbing fixtures and, in effect, make higher-volume products unavailable 

to consumers, state and local standards typically apply only to the 

installation of efficient fixtures. Thus, reinstating state and local standards 

would not affect the manufacture of higher-volume fixtures or prevent the 

sale of such products in neighboring jurisdictions.
Page 31 GAO/rced-00-232 Low-Flow Toilets

Appendix III

Summary of Accelerated Toilet Replacement 

Programs in Six Localities ApendxiI

a

Costs include other conservation efforts, such as showerhead and clothes-washer rebates, 

but the primary costs are for toilets.

b

A New York City official attributed the higher savings per toilet in that city to the 

replacement of older, higher-volume toilets (5- to 7-gallons-per-flush toilets installed prior to 

1950) in high-density neighborhoods. 

c

In May, we reported that the cost of the Tampa program was $1.2 million dollars. Since 

then, a program official provided us with revised cost data. (See GAO/RCED-00-161R, May 1, 

2000.)

Location

Period covered by

program statistics

Number of

toilets

distributed

free or through

rebate

program

Estimated water

savings per toilet

(gal. per day)

Total

estimated

water savings

(gal. per day)

Cost of toilet

program

Austin, Tex. 1992-Sept. 1999 48,222 29.3 1,400,000 $2.0 million

Los Angeles, Calif. 1990-Feb. 2000 905,923 31.7 28,700,000 107 milliona

New York, N.Y. 1994-Apr. 1996 1,300,000 53.8b 70,000,000 290 million

Phoenix, Ariz. 1994-Mar. 2000 1,226 25.6 78,464 96,000

Tampa, Fla. 1993-Sept. 1999 15,263 29.1 440,400 1.7 millionc

Hillsborough County, Fla. 1994-Sept. 1999 60,305 23.4 1,400,000 8.8 million

Total 2,330,939 102,018,864
Page 32 GAO/RCED-00-232 Low-Flow Toilets

Appendix IV

Projected Reduction in Water Consumption by 

2010 and 2020, by Location ApendxiIV

Projected water use and savings in millions of gallons per day

Average daily water use Projected daily water savings

Location Population Year

Without water

efficiency

standards

With water efficiency

standards Amount Percentage

Austin, Tex., City of Austin 

Water & Wastewater 

Utility

650,000 2010 167.5 160.8 6.7 4.0

2020 230.9 215.2 15.7 6.8

Boston, Mass., Boston 

Water & Sewer 

Commission

650,000 2010 84.2 81.0 3.2 3.8

2020 85.1 79.4 5.7 6.7

Cary N.C., Town of Cary 84,779 2010 16.1 15.1 1.0 6.2

2020 23.1 21.0 2.1 9.1

Clarksburg, W. Va., 

Clarksburg Water Board 

19,000 2010 2.9 2.8 0.1 3.4

2020 3.6 3.4 0.2 5.5

Fort Worth, Tex., Fort 

Worth Water Department

753,116 2010 170.0 166.6 3.4 2.0

2020 178.8 172.9 5.9 3.3

Laurel, Md., Washington 

Suburban Sanitary 

Commission

1,700,000 2010 206.3 199.7 6.6 3.2

2020 224.1 212.0 12.1 5.4

Los Angeles, Calif., Los 

Angeles Department of 

Water & Power

3,800,000 2010 560.6 542.1 18.5 3.3

2020 560.3 527.8 32.5 5.8

Michigan City, Ind., 

Michigan City Department 

of Water 

41,000 2010 12.1 11.7 0.4 3.3

2020 12.7 12.0 0.7 5.5

Oceanside, Calif., City of 

Oceanside Water

157,869 2010 37.5 36.6 0.9 2.4

2020 46.2 44.4 1.8 3.9

Phoenix, Ariz., Phoenix 

Water Services

1,252,425 2010 341.4 331.5 9.9 2.9

2020 393.6 375.1 18.5 4.7

Pinellas County, Fla., 

Pinellas County Utilities 

643,191 2010 84.4 80.6 3.8 4.5
Appendix IV

Projected Reduction in Water Consumption 

by 2010 and 2020, by Location

Page 33 GAO/RCED-00-232 Low-Flow Toilets

Note: Population data are as of 1999. 

Source: Analysis conducted by Maddaus Water Management for the American Water Works 

Association. Using data provided by Maddaus Water Management, we calculated the average daily 

water use with and without the water efficiency standards. 

2020 89.9 82.8 7.1 7.9

Rockford, Ill., City of 

Rockford Water Division 

150,000 2010 46.7 44.6 2.1 4.5

2020 62.5 58.5 4.0 6.4

Syracuse, N.Y., City of 

Syracuse Department of 

Water

235,000 2010 40.7 39.6 1.1 2.7

2020 38.8 36.9 1.9 4.9

Tacoma, Wash., Tacoma 

Water

306,000 2010 80.8 78.7 2.1 2.6

2020 92.1 88.6 3.5 3.8

Tampa, Fla., City of 

Tampa Water Department

450,000 2010 77.4 75.0 2.4 3.1

2020 81.5 77.1 4.4 5.4

Wausau, Wis., Wausau 

Water Works

45,000 2010 6.3 6.1 0.2 3.2

2020 5.4 5.1 0.3 5.6

Total 10,937,380 2010 1,934.9 1,872.5 62.4 3.2

2020 2,128.5 2,012.1 116.4 5.5

(Continued From Previous Page)

Projected water use and savings in millions of gallons per day

Average daily water use Projected daily water savings

Location Population Year

Without water

efficiency

standards

With water efficiency

standards Amount Percentage
Page 34 GAO/RCED-00-232 Low-Flow Toilets

Appendix V

Projected Investments in Drinking Water 

Infrastructure by the Year 2020, by Location ApendxiV

a

Using a 7-percent discount rate, the savings would be $165.7 million.

Source: Analysis conducted by Maddaus Water Management for the American Water Works 

Association.

Dollars in millions

Investment projected through 2020, discounted at 3 percent

Location

Without water efficiency

standards

With water efficiency

standards

Amount of

savings

Percent

savings

Austin, Tex., City of Austin Water & 

Wastewater Utility

$363.5 $347.8 $15.7 4.3

Boston, Mass., Boston Water & 

Sewer Commission

820.7 788.6 32.1 3.9

Cary N.C., Town of Cary 108.9 103.0 5.9 5.4

Clarksburg, W. Va., Clarksburg Water 

Board 

8.5 8.3 0.2 2.4

Fort Worth, Tex., Fort Worth Water 

Department

1,008.7 986.4 22.3 2.2

Laurel, Md; Washington Suburban 

Sanitary Commission

360.3 339.3 21.0 5.8

Los Angeles, Calif., Los Angeles 

Department of Water & Power

1,722.8 1,663.6 59.2 3.4

Michigan City, Ind., Michigan City 

Department of Water 

12.7 12.4 0.3 2.4

Oceanside, Calif., City of Oceanside 

Water 

189.3 184.2 5.1 2.7

Phoenix, Ariz., Phoenix Water 

Services

441.4 428.1 13.3 3.0

Pinellas County, Fla., Pinellas County 

Utilities 

491.1 465.9 25.2 5.1

Rockford, Ill., City of Rockford Water 

Division 

72.0 68.8 3.2 4.4

Syracuse, N.Y., City of Syracuse 

Department of Water

231.2 224.8 6.4 2.8

Tacoma, Wash., Tacoma Water 302.3 300.3 2.0 0.7

Tampa, Fla., City of Tampa Water 

Department

209.5 190.8 18.7 8.9

Wausau, Wis., Wausau Water Works 8.1 7.7 0.4 4.9

Total $6,351.0 $6,120.0 $231.0a 3.6
Page 35 GAO/RCED-00-232 Low-Flow Toilets

Appendix VI

Scope and Methodology ApendxiVI

In conducting our review, we collected information from a wide variety of 

sources, including the Environmental Protection Agency’s (EPA) Office of 

Ground Water and Drinking Water and Office of Wastewater Management, 

the Department of Energy’s Office of Energy Efficiency and Renewable 

Energy, the American Society of Mechanical Engineers, the American 

National Standards Institute, the American Water Works Association, the 

Association of Metropolitan Sewerage Agencies, the California Urban 

Water Conservation Council, plumbing manufacturers and contractors, and 

selected states and localities. We contacted 16 states and 5 of the 6 

localities that adopted standards for water-efficient plumbing fixtures 

before the national standards took effect,1

 to wit: Arizona; California; 

Connecticut; Delaware; Georgia; Maryland; Massachusetts; Nevada; New 

Jersey; New York; North Carolina; Oregon; Rhode Island; Texas; Utah; 

Washington; Dade County, Florida; Denver, Colorado; Hillsborough County, 

Florida; Palm Beach, Florida; and Tampa, Florida. In addition, we visited 

six localities (Austin, Tex.; Los Angeles, Calif.; New York, N.Y.; Phoenix, 

Ariz.; Tampa, Fla.; and Hillsborough County, Fla.) to collect more detailed 

information on accelerated toilet replacement programs. The criteria used 

to select these locations included (1) their use of water efficiency 

standards, which preceded the national standards; (2) their use of rebate 

and/or retrofit programs to accelerate the installation of low-flow toilets 

and other water-efficient fixtures; and (3) an assessment of the programs’ 

impact on water consumption. 

We also obtained and analyzed relevant documents and reports, including 

the applicable regulations; performance standards for low-flow toilets; and 

a variety of studies on the impact of water-efficient plumbing fixtures. For a 

complete list of the studies we reviewed, see the Bibliography.

To obtain information on the estimated impact of the national water 

efficiency standards on water consumption levels and wastewater flows, 

we reviewed studies that examined the use and impact of water-efficient 

plumbing fixtures, including (1) studies that made precise measurements 

of water use in a limited number of households, (2) studies that estimated 

impacts for an entire locality, and (3) two major studies of the impacts on 

water consumption and wastewater flows being sponsored by the 

American Water Works Association and EPA, respectively. To the extent 

1

In one case (Palm Beach, Florida), our contact was limited to verifying local standards for 

water-efficient plumbing fixtures; we did not conduct a semistructured interview to discuss 

other issues.
Appendix VI

Scope and Methodology

Page 36 GAO/RCED-00-232 Low-Flow Toilets

possible, we reviewed the reasonableness of the methodology and 

assumptions used in the studies. We also collected information on how well 

the low-flow fixtures work and how they are used in practice by reviewing 

customer satisfaction surveys administered to participants in accelerated 

replacement programs and interviewing plumbing manufacturers and 

contractors and representatives of the American Society of Mechanical 

Engineers and the American National Standards Institute. To obtain 

information on the extent to which water-efficient fixtures might be used in 

the absence of the national standards, we conducted semistructured 

interviews with and collected documentation from the 16 states and 4 of 

the 6 localities that adopted their own standards before the national ones 

took effect. In addition, we collected data on accelerated toilet 

replacement programs and interviewed plumbing contractors involved in 

performance-based contracting.

For information on the potential impact of repealing the national 

standards, we reviewed studies that examined the timing and cost of local 

infrastructure investments with and without the standards in place. We 

relied primarily on data and case studies developed for ongoing studies 

being sponsored by the American Water Works Association and EPA. To the 

extent feasible, we reviewed the reasonableness of the methodology and 

assumptions used in the studies we examined. In looking at local 

communities’ ability to finance additional investments in infrastructure, we 

extracted information from EPA’s needs surveys for drinking water and 

wastewater treatment infrastructure and a more recent needs estimate by 

the Water Infrastructure Network—a coalition of various utility, 

government, and public works associations. We also addressed this issue—

and the likelihood of constraints on new construction if the national 

standards were repealed—during our interviews with officials from states 

and localities with preexisting standards for water-efficient plumbing 

fixtures.
Page 37 GAO/RCED-00-232 Low-Flow Toilets
Page 38 GAO/RCED-00-232 Low-Flow Toilets

Bibliography

The Conserving Effect of Ultra Low-flush Toilet Rebate Programs. A&N 

Technical Services, Inc. A Report Submitted to the Metropolitan Water 

District of Southern California. June 1992.

Ultra Low-Flush Toilets in Commercial Installations Prepared for California 

Urban Water Agencies and California Urban Water Conservation Council. - - 

- - -. California Urban Water Agencies and California Urban Water 

Conservation Council. Feb. 1994.

Ultra Low-Flush Toilet Programs, Evaluation of Program Outcomes and 

Water Savings. - - - - -. A Report Submitted to the Metropolitan Water 

District of Southern California. July 1995.

Technical Issues and Recommendations on the Implementation of the U.S. 

Energy Policy Act. Amy Vickers & Associates, Inc. Prepared for American 

Water Works Association, Washington, D.C.: Oct. 25, 1995.

Regional Water Supply Demand Management Plan. - - - - -. West Coast 

Regional Water Supply Authority. Clearwater, Fla.: June 1997.

Seattle Public Utilities and U.S. Environmental Protection Agency Home 

Water Conservation Study Preliminary Results. Aquacraft, Inc., as of July 

2000.

Project Report: Measuring Actual Retrofit Savings and Conservation 

Effectiveness Using Flow Trace Analysis. Aquacraft Water Engineering & 

Management. Boulder, Colo.: May 16, 1996.

Residential End Uses of Water. American Water Works Association 

Research Foundation. Dec. 1999.

Water Conservation: Survey of Programs and Potential Benefits to County 

Sanitation Districts of Orange County. Camp Dresser & McKee. Orange 

County, Calif.: June 1997.

City of Austin, Texas, Environmental and Conservation Services 

Department. Ultra Low-Flow Toilet Demonstration Project Evaluation. City 

of Austin, Tex. June 1991.

The CII ULFT Savings Study, Final Report. Hagler Bailly Services, Inc. 

Sponsored by the California Urban Water Conservation Council. Aug. 5, 

1997.
Bibliography

Page 39 GAO/RCED-00-232 Low-Flow Toilets

Ultra Low-Flush Toilets, Customer Satisfaction Survey, 1999 Residential 

Customer Satisfaction Survey. Honeywell DMC Services, Inc. Metropolitan 

Water District of Southern California. Dec. 1999.

City of Boulder Water Conservation Futures Study. Hydrosphere Resource 

Consultants, Inc., Aquacraft, Inc. July 29, 1999.

City of Houston Water Conservation Plan. Montgomery Watson. May 1997.

Water Closet Survey. National Association of Home Builders Research 

Center. Sept. 1999.

Water Saving Plumbing Fixture Retrofit and Rebate Programs. New York 

City, Department of Environmental Protection, Bureau of Water and 

Energy Conservation. Sept. 1992.

New York City Water Conservation Programs: A Summary. New York City, 

Department of Environmental Protection. July 1999.

Ultra Low-Flush Toilet Distribution Program, Comparison of Customer 

Survey Results. Peak International. Metropolitan Water District of Southern 

California. Apr. 1996.

Saving Water, Saving Dollars: Efficient Plumbing Products and the 

Protection of America’s Water. Potomac Resources, Inc. Apr. 1998.

Performance of Ultra Low-Volume Flush Toilets in Phoenix, Arizona. RSE 

Group/Ayres Associates. City of Phoenix: Feb. 1986.

East Bay Municipal Utility District Water Conservation Study (Report No. 

R219). Stevens Institute of Technology. Prepared for East Bay Municipal 

Utility District. Oakland, Calif.: Oct. 1991.

A Laboratory and Field Evaluation of 1.6 GPF Water Closets in a 

Commercial Setting (Report No. R 246). - - - - -. Prepared for the City and 

County of Denver. Denver, Colo.: Oct. 1992.

The Impact of Water Conserving Plumbing Fixtures on Residential Water 

Use Characteristics: A Case Study in Tampa, Florida. - - - - -. City of Tampa, 

Fla.: Feb. 1993.
Bibliography

Page 40 GAO/RCED-00-232 Low-Flow Toilets

Water for Texas, A Consensus-Based Update to the State Water Plan. Texas 

Water Development Board. Aug. 1997.

Estimated Use of Water in the United States in 1995. U. S. Department of 

the Interior. U.S. Geological Survey Circular 1200. 1998.

1996 Clean Water Needs Survey Report to Congress. U.S. Environmental 

Protection Agency. Environmental Protection Agency, Office of Wastewater 

Management.

1997 Drinking Water Infrastructure Needs Survey First Report to Congress. 

- - - - -. Environmental Protection Agency, Office of Water. Jan. 1997.

Customer Satisfaction Survey Final Report. Westat, Inc. New York City, 

Department of Environmental Protection. Dec. 1996.

Evaluation of New York City’s Toilet Rebate Program. - - - - -. New York City, 

Department of Environmental Protection. May 1997.

A Survey of Purchaser Opinions About Ultra Low Flush Toilets. The 

Wirthlin Group. Los Angeles Department of Water and Power. July 1992.

A Survey of Ultra-Low-Flush Toilet Users. - - - - -. Los Angeles Department 

of Water and Power. Oct. 1995.

A Long Term Satisfaction Survey of Ultra Low-Flush Toilet Users. Wirthlin 

Worldwide. Los Angeles Department of Water and Power. Mar. 1996.

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