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!

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.

For more information:
California Urban Water Conservation Council (CUWCC)

United States EPA, Water Sense