Toilet Fixtures

Drainline Studies | Flappers & Flush Valve Seals | High Efficiency Toilets (HETs) |
Maximum Performance (MaP) Testing & Uniform North American Requirements (UNAR)
Plumbing Standards | Ultra Low Flow Toilets (ULFTs)

Toilet fixture replacement represented one of the most popular water efficiency initiatives of the 1990s, as drought conditions motivated water providers to implement water conservation programs. In these programs, older 3.5- and 5.0-gallons per flush (gpf) toilet fixtures in residences were replaced with 1.6-gpf fixtures. Today, many water providers with aggressive replacement programs are approaching a level of “saturation” in their residential sector wherein the majority of residential toilet fixtures are 1.6-gpf models. Therefore, many water providers have moved on to other priorities in their conservation programs.

As the number of bathrooms in housing steadily increases, and, in some cases, the number of occupants decreases, development of cost=effectiveness information related to toilet replacement programs must address just WHICH TOILETS within a residence should be replaced, e.g., all of them, the most-used toilet, the oldest toilet, the toilet with the highest flush volume, or ??? To aid in this analysis, we have compiled some national numbers on toilet "density". Download the table that shows density during the period from 1970 to 2003.

Two types of toilet fixtures dominate the marketplace: ULFTs (Ultra-Low Flush Toilets – aka “low flow” or “ultra-low-flow”) and HETs (High-Efficiency Toilets). ULFTs are defined by a flush volume in the range between 1.28-gpf and 1.6-gpf, while HETs are defined as 1.28-gpf or less. Several different technologies are used by the manufacturers to achieve these flush volumes. Those technologies are NOT all equal in flush performance or cost. The following sections provide information on both technologies.

Caution on Dual Flush Conversion Devices

The recommendations or subsidizing of untested products such as the dual-flush conversion devices for tank type toilets are in question. Many products such as these provide the ability to convert a 1.6 gallon, 3.5 gallon, 5 gallon, or more fixture from a single-flush, tank-type gravity toilet to a dual-flush toilet, which all promise water savings. There is no independent evidence that savings do or will occur as a result of retrofitting the toilet with these devices. For reasons and more information see the memo below.

Caution on Dual-Flush Conversion Devices for Tank-Type, Gravity-Fed Toilets