High-Efficiency Toilets (HETs)
Drainline Studies
Specifications and Test Protocols
UNAR
Los Angeles SPS
MaP Testing
U.S. EPA WaterSense
Plumbing Standards
Ultra-Low-Flush Toilest (ULFTs)
Commercial Flushometer Valve/Bowl Testing
NAHB Research Center Testing
Flappers & Flush Valve Seals

HIGH-EFFICIENCY TOILETS (HETs)

The HET is defined as a fixture that flushes at 20 percent below the 1.6-gallons-per-flush/6.0-liters-per-flush (gpf/lpf) U.S. maximum or less, equating to a maximum of 1.28-gpf/4.8-lpf. (NOTE: The HET category includes dual-flush fixtures.) This 20 percent reduction threshold serves as a metric for water authorities and municipalities designing more aggressive toilet replacement programs and, in some cases, establishing an additional performance tier for their financial incentives (e.g., rebate and voucher programs). It is also a part of the water-efficiency element of many green building programs in the U.S.

HETs have been available in the marketplace here in California since 1999 and, today, 23 different toilet manufacturers are marketing over 200 such models of fixtures! So, HETs are NOT a new phenomenon, but have existed in the marketplace for more than 9 years. During that time, new fixture models have been introduced and, most importantly, the performance of HETs has improved dramatically. Today, HETs outperform their ULFT (1.6-gpf) predecessors AND the 3.5-gpf toilets that were installed in the 1980s!

Following are some of the documents that you may find useful:

February 1, 2007 A Primer on HETs
A little bit of history on HETs, a definition of the term, a brief explanation of how well HETs perform in comparison to ULFTs, and discussion of drainline issues...all of this in a short 2-page Primer!
- Primer on Hets (PDF)

August 21, 2007 HETs- An Up-To-Date List (PDF)
The recent explosion in the number of models of HETs has led us to list all of the fixtures that currently appear to be qualified to use that designation. This list is periodically updated as new models are introduced or older models are dropped from product lines. This new list includes the first of the Flushometer Valve HET combinations. NOTE: Manufacturers are asked to notify us when new HET models become available, providing specification sheets when available.
- HET(PDF)

Aggressive HET Programs in California, Colorado, Washington and Massachusetts!
Water utilities have implemented a large number of different local and regional programs that encourage the replacement of older toilets with HETs...and more programs are in development. Check this list for program details, for the individuals to contact for more information, and for the program-specific websites. NOTE: The contact names and phone numbers on this spreadsheet are for the use of water providers and product manufacturers. This contact information is NOT to be used by manufacturers or retailers in their advertising or other promotional material.
- HET PROGRAMS (PDF)

What about CUSTOMER SATISFACTION with HETs? The question of customer satisfaction with HETs at their lower flush volumes has been asked repeatedly over the past few years. Will customers accept the noise of the flush action associated with a pressure-assist HET? Will customers use the dual-flush features on those HETs as intended? Do HETs experience unacceptable levels of "double-flushing"? Will there be any reports of drainline problems due to reduced water flows? Answers to some of these questions (and others) are beginning to surface as water providers survey their customers in connection with their ongoing HET programs. Two recent presentations shed some light:

(1) The Santa Clara Valley Water District (San Jose, Calif) has replaced over 1,000 water-wasting toilets in COMMERCIAL applications with pressure-assist HETs (1.0-gallons per flush and less). Check Karen Morvay's presentation that describes the program and anecdotal customer satisfaction findings.
- Santa Clara Valley HETs (PDF)

(2) Redwood City, Calif has replaced over 4,000 water-wasting toilets in RESIDENTIAL dwellings, including both dual-flush Caroma HETs, pressure-assist 1.0-gallon HETs, and a few 1.6-gallon ULFTs. Examine Manny Rosas' presentation for program information and customer satisfaction statistics.
- Redwood City HETs (PDF)

HETs as a Best Management Practice? (2005)
An analysis of the installed base of residential and non-residential toilets in California was completed as part of an assessment of HETs being considered for Potential Best Management Practice (PBMP) status. This 2005 report examines the potential water savings that might result from implementing various program scenarios directed at replacing some or all of the existing installed base and/or focusing entirely on new construction.
http://www.cuwcc.org/uploads/tech_docs/PBMP_Report_Year2_HETs_Urinals_Nov-2005.pdf

Jordan Valley (Utah) Study of ULF Toilet Fixtures (2003)
The Jordan Valley Water Conservancy District installed 275 new toilet fixtures in residential dwellings and then measured the water savings and customer satisfaction. Fixture models included the Caroma Tasman dual-flush HET, Niagara Flapperless ULFT, and the Gerber Aquasaver ULFT. This excellent study by Paula Mohadjer carefully documents a very detailed comparison among the three quite different toilets.
- Jordan Valley study

Dual Flush High-Efficiency Toilet (HET) Fixtures
Five authoritative field studies measured the water savings resulting from the installation and use of dual-flush high-efficiency toilet fixtures. This paper summarizes the results of those studies with respect to dual-flush toilet use.
- Dual Flush Fixtures Study Summary (PDF)

The five field studies may each be downloaded individually:
- SWEEP Study Report (PDF)
- CMHC Dual-Flush Report (PDF)
- FINAL REPORT - SEATTLE PUBLIC UTILITIES (PDF)
- FINAL REPORT - EAST BAY MUD (PDF)
- Jordan Valley study (PDF)

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Will HETs provide sufficient water to move waste in drainlines?

February 20, 2007 Drainline Testing in Australia
An article in the latest issue of World Plumbing Review (Issue 1 for 2007) covers extensive drainline waste transport testing performed by Caroma in Australia. Once you get through some of the sales "pitch" for Caroma products, there are some interesting observations in this article.
- Testing Times Down Under (PDF)

February 20, 2007 WaterSense Program Sponsors Additional Drainline Testing
As part of the analyses conducted on behalf of the U.S. Environmental Protection Agency's WaterSense Program, additional drainline testing was performed to establish that WaterSense HETs were, in fact, suited to residential applications. This testing regime used the same testing media as the Canadian study described above.
- WaterSense Drainline Testing Results (PDF)

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VOLUNTARY SPECIFICATIONS AND TEST PROTOCOLS

The following 4 sets of specifications and testing protocols were developed by water provider interests. Compliance by manufacturers with each one is voluntary.

1) UNAR–UNIFORM NORTH AMERICAN REQUIREMENTS for toilet fixtures

What is UNAR….and why was it necessary?
For a number of years, individual water agencies and municipalities in both the U.S. and Canada have been developing toilet specifications and "approved lists" that were sometimes quite arbitrary in their development and were frequently different from one another. It became apparent to both the water conservation specialists AND the plumbing industry that a new direction would benefit everyone - water conservation programs, the plumbing industry and, of course, the consumer looking for the rebate! Thus, the idea was born that a set of common requirements would help to end much of the confusion.

UNAR for toilet fixtures is based partly upon the Los Angeles SPS (see below), and partly upon MaP testing of toilet fixtures (ww.cuwcc.org/maptesting.lasso). It incorporates important criteria focused on sustainable water savings and has been endorsed by water suppliers as well as plumbing industry representatives. UNAR encompasses two tiers of performance: conventional toilet fixtures flushing at 1.3 to 1.6 gallons AND HETs flushing at 1.28 gallons or less. For more information, download the UNAR specification and the lists of currently qualified toilet fixtures:
- UNAR SPECIFICATION (PDF)
- *Revised! (May 2008)* UNAR-QUALIFIED CONVENTIONAL TOILET MODELS (PDF)
- *Revised! (June 2008)* UNAR-QUALIFIED HIGH EFFICIENCY TOILET (HET) MODELS (PDF)
- February 2007 UNAR SPECIFICATION Version 1.2 (PDF)

2) SPS – SUPPLEMENTARY PURCHASE SPECIFICATION for toilet fixtures

Los Angeles Supplementary Purchase Specification (SPS) for Toilet Fixtures (Applies to BOTH ULFTs and HETs)
The SPS applies to toilet purchases under the Los Angeles Department of Water and Power’s Toilet Distribution Program. Compliance with the specification by toilet fixture manufacturers is entirely VOLUNTARY. It was initially adopted as requirement in 2000. As was originally planned, the specification changed its adjustability maximum for ULFTs from 2.4 gallons to 2.0 gallons, effective July 1, 2003. (Note: there are NO PLANS to lower this threshold.) The following documents provide information on this specification:
- SPS Explanatory Memo
- SPS - ULFT Requirements
- SPS-Certified Toilet Fixtures - Gravity and Vacuum
- SPS-Certified Toilet Fixtures - Pressure-Assist
- SPS-Certified Flappers
- SPS Questions and Answers

NOTE: The provisions in the SPS relating to flapper durability and marking of essential repair information inside the tank have been incorporated into the ASME/ANSI A112.19.5 national standard.

3) MaP – MAXIMUM PERFORMANCE testing of toilet fixtures

December 2007ELEVENTH EDITION UPDATE TO MaP™ TESTING REPORT ON TOILETS:
This Eleventh Edition of the original Maximum Performance (MaP™) testing report is now available. It provides the latest information on toilet fixture performance in two reader-friendly formats!

1) The conventional format that provides all of the technical performance detail on the 600 different toilet fixture models.

2) A "CONSUMER-FRIENDLY" condensed format, black & white only, easy-to-read, and providing just the essentials needed to shop or specify a fixture for home or business!

3) Appendices B and C seperately with only the listings of m odels and the test results, but without the other information.

4) Seperate listings for gravity-fed tank-type toilets, pressure and power assisted toilets, and flushometer valve toilets.

The toilet fixture models are listed with their MaP performance scores and physical characteristics. Go HERE to visit our MaP™ testing page and download the needed documents.

4) U.S. Environmental Protection Agency - WaterSense

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Plumbing Standards

March 2007 Evaluating the current toilet certification test media This laboratory study evaluated the current testing media used in the U.S. and Canada to certify toilet fixtures for sale and installation here. Testing with sponges and plastic balls and pellets are required in both the U.S. and Canadian plumbing standards, but how realistic is any test that uses such materials to test for flush performance? This study report is a first scientific step in examining how test results using these materials compare with those obtained through MaP testing.
- Toilet Test Media Evaluation Report March 06, 2007 (PDF)

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ULTRA-LOW-FLUSH TOILETS (ULFTs-1.6-gpf)

Testing of Popular Flushometer Valve/Bowl Combinations (Commercial) (2005)
While there has been considerable research into the performance and water savings related to residential toilet fixtures (typically gravity-fed), little work has been completed on flushometer valve fixtures for commercial applications. This flushometer testing program included flush volume and performance testing of seven popular commercial bowl models with seven different flushometer valves, for a total of 49 different bowl/valve combinations. Included within the study were measurements of the variations in flush volume that could be achieved with adjustments of the flush valves or the control stop. This study was sponsored by the City of Toronto, and the Regions of Durham and Waterloo in Ontario, Canada. For a PDF copy of the revised Final Report, download it from the website of Canadian Water and Waste Water Association:
- Flushometer Study (PDF)

Performance Testing of Wall-Mount Siphon-Jet Flushometer Toilet Fixtures (Commercial) (2003)
Seattle Public Utilities funded a comprehensive 2003 study of the flush performance of 28 flushometer toilets (8 different models) coupled with 34 manually operated flushometer valves (6 models), all of which were installed on the campus of the University of Washington. A battery of tests was run on each of the eight toilet models that included various combinations and amounts of test media consisting of toilet paper, seat protectors, tofu, and concentrated brine solution. Download a copy of the study report for further information, however, readers should be aware of the following CAUTION by Seattle Public Utilities and the CUWCC:

NOTE: This research is not intended as a selection guide for commercial toilets and flush valves. The site-specific performance requirements (weighting criteria) in the report are specific to the facility staff at the University of Washington. The author cautions readers not to directly apply the rankings or results of this research to other sites or locations without further testing. Under different circumstances and using different testing protocols and larger sample sizes, much different results, rankings, and conclusions could be obtained. Few research studies have attempted to document flushing performance outside the lab due to the many variables that exist. This paper documents variations in actual flushing performance between lab tests and functional installations. We hope that this research will stimulate more realistic laboratory and field testing protocols.

Download the study:
- Performance Test-UW (PDF)

Roger van Gelder, P.E., consultant to Seattle Public Utilities, was the project manager for the testing and analysis. Roger may be reached as follows:
Email: rogervangelder@aol.com
Telephone: 206-615-1257

Jordan Valley (Utah) Study of ULF & HE Toilet Fixtures (2003)
The Jordan Valley Water Conservancy District installed 275 new toilet fixtures in residential dwellings and then measured the water savings and customer satisfaction. Fixture models included the Caroma Tasman dual-flush HET, Niagara Flapperless ULFT, and the Gerber Aquasaver ULFT. This excellent study by Paula Mohadjer carefully documents a very detailed comparison among the three quite different toilets.
- Jordan Valley Study

NAHB Research Center Low-Flow Toilet Study (2002)
The National Association of Home Builders Research Center, in cooperation with Seattle Public Utilities and the East Bay Municipal Utility District of Oakland, CA, released the water closet fixture performance study that was underway for much of 2002. The report details the results of extensive performance testing (with sponges and paper wads) on 49 of the most popular low-flow toilets in the United States and Canada.

NOTE: The results of the NAHBRC testing are not meant to be a direct assessment of which toilets will or will not perform well in a home environment. Only two samples of each toilet model were tested, and the material used in the testing may not be an appropriate substitute for measuring “real-world” toilet performance.

NOTE: Recognizing that the use of sponges and paper wads might not accurately replicate “real-world” demands placed upon a toilet fixture, this study was followed by the development of the MaP testing protocol in 2003 by 22 water provider interests. Many believe that the MaP testing may provide a more realistic assessment of toilet fixture performance than the results of this NAHBRC study.

- Download the Summary NAHBRC Test Report: Water Closet Performance Testing
- Performance ranking of all models in the NAHBRC test
- Top performing toilets in the NAHBRC test that are priced under $100
- A side-by-side comparison of the NAHBRC study results with those reported by Consumers Reports

Customer Satisfaction Survey (gravity-fed residential toilets) (1999)
In 1999, the Metropolitan Water District commissioned Honeywell DMC to perform a survey of 1,300 individuals who installed new gravity-fed 1.6-gpf toilets in 1998 and 1999. A total of 13 different toilet models were rated by customers on a variety of important performance factors, the results being reported in this document:
- ULFT Customer Satisfaction Survey (PDF)

Long-term Durability of Toilet Fixtures (2001)
In 2001, the Metropolitan Water District undertook to test three new toilet models that had recently been introduced into the marketplace. Eight fixtures were each subjected to 250,000 flush cycles. Where potential problems appeared, manufacturers addressed those problems and improved products resulted.
- ULFT Durability Test Report (PDF)

Testing of Toilet Fixtures Against Proposed National Standards (2000)
In 2000, 15 water providers in the U.S. sponsored a comprehensive toilet testing program at the Stevens Institute of Technology. Designed to evaluate the efficacy of a proposed new test protocol for the national standard, this year-long effort compared the performance of 18 different gravity-fed and pressure-assist toilet models.
- Stevens Lab Test Report (PDF)

Functioning of Aging ULF Toilets in Tucson AZ (2000)
This 2000 study, sponsored by the City of Phoenix and the U.S. Bureau of Reclamation, is a "one-of-a-kind" project, because it is the only study that has looked at ULF toilet fixtures of 1991-92 vintage to see how they were performing after 8 years of use. The University of Arizona Research Center data logged 170 homes and analyzed the results for flush volume, double-flushing, leakage and other factors. This was followed by household surveys to determine the types of installed toilet fixtures and owner satisfaction with those fixtures.
- Study of Aging ULF Toilets (PDF)

Toilet Flush Volume Study (2001)
This just-released comprehensive field study from 2001 documents some very interesting characteristics of common gravity-fed toilet fixtures. In particular, ULF toilets operating at abnormally low flush volumes (well below their rated flush volume of 6 liters - 1.6-gallons) were field measured to determine just what was really happening inside the home. That is, how could a 1.6-gallon toilet function at half that volume of water? What was discovered may or may not surprise you!
- FINAL REPORT - DURHAM FIELD STUDY (PDF)

Effectiveness of Data Logging Residential Water Meters to Identify and Quantify Toilet Flush Volumes: A Pilot Study (2004)
This study examines the potential to incorrectly identify toilets and their flush volumes when using data loggers to monitor water use within a residential dwelling. Conducted in June, 2004, on behalf of the Metropolitan Water District of Southern California, this study's final report was just recently released for distribution.

NOTE: Because of the nature of the conclusions and recommendations within the study, Aquacraft, Inc., a proponent of the use of this technology along with their Trace Wizard© software, provided a response explaining how identification issues are dealt with through the most recent version of the software. You are urged to download and read both documents:

- Data Logging Residential Water Meters (PDF)
- Discussion and Response by Aquacraft, Inc. (PDF)

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FLAPPERS & FLUSH VALVE SEALS

CUWCC Toilet Flapper Study (2004)
This comprehensive field study of the durability of toilet flappers, and the habits and practices of homeowners with respect to flapper replacement and use of in-tank bowl cleaning tablets, involved the inspection of 892 randomly selected toilet fixtures in homes throughout California. Products from 14 manufacturers with production dates from 1992 to 2002 were measured for flush volume and subjected to a flapper inspection. The final study report may be purchased from the CUWCC by going to the PUBLICATIONS PAGE. (Cost is $10)

Flapper Materials Durability Studies (1994-2000)
These three laboratory studies by the Metropolitan Water District of Southern California were a catalyst in the plumbing industry’s advancements in flapper materials durability. As chlorine-based drop-in bowl cleaning tablets made their way into the consumer marketplace (and into their toilet tanks), flapper failure and toilet leakage became a significant concern of the plumbing industry and the water authorities. Beginning in 1994 and working together, more durable products resulted. Download all three study reports here:
- Flapper Materials Study #1 Report: 1998 (PDF)
- Flapper Materials Study #2 Report: 2000 (PDF)
- Flapper Materials Study #3 Report: 2001 (PDF)

Toilet Flappers - A Brief History of Problems
Why are toilet flappers getting so much attention from water conservation professionals? Read about the evolution of the flapper problems through the 1990s until today:
- Toilet Flappers - Weak Link of Water Conservation

After-Market Toilet Flappers: Compatibility and Flush Volumes (1998)
This 1998 Metropolitan Water District study focused on the compatibility of flappers found in the traditional after-market (at Home Depot, Lowe’s, and hardware stores) with the typical gravity-fed toilet fixtures found in most residential households. A total of 50 aftermarket flappers were fitted to 24 different toilets. Flush volumes were measured and reported in this document:
- After Market Flapper Study Report (PDF)

Flapper Replacement - Marketing Strategies Report (2004)
Outreach and marketing strategies directed at encouraging customers to replace aging and leaking flappers is the subject of this final report. Tampa Bay Water, its participating member governments, and consultants developed a variety of methods and tools to aid customers. Download this report, read about those approaches, and access their large database of toilet fixtures and replacement flappers.
- Flapper Marketing Strategies Report (PDF)

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