Toilet Fixtures
Drainline Studies | MaP and UNAR | Plumbing Standards | Ultra Low Flow Toilets (ULFTs) | Flappers & Flush Valve Seals
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, 18 different toilet manufacturers are marketing over 95 such models of fixtures! So, HETs are NOT a new phenomenon, but have existed in the marketplace for more than 7 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:
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)
CAUTION On Flushometer Valve Toilet Installations in Existing Commercial Buildings (PDF)
Read this statement relating to potential drainline issues associated with the replacement of high-volume flushometer toilets in certian types of non-residential applications. This caution applies primarily to certain types of facilities with certain types of drainline conditions.
- Flushometer Toilet Installations CAUTION
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.
-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)