The WaterSense Program was conceived by the U.S. EPA in 2004 as a water efficient product labeling program. In 2006, WaterSense released its specification for tank-type HET’s. Today, over 1,740 toilet models meet the rigorous requirements of WaterSense and may be labeled with the WaterSense mark. The maximum flush volume of WaterSense tank-type toilet fixtures is 1.28 gallons (4.8 litres), with a special provision for dual-flush toilet models
One of the more significant requirements is that WaterSense labeled high-efficiency toilets must meet a minimum MaP threshold of 350 grams of waste removed from the toilet fixture in a single flush (including toilet paper). The MaP search tool allows you to confine your search to WaterSense-approved toilets OR go here to view the full listing of WaterSense labeled high-efficiency toilets.
The WaterSense Program also qualifies and labels flushing urinals (fixture and flush valve) for commercial installations. The maximum flush volume for these fixture combinations is 0.5 gallons (1.9 litres) or less as called for in the approved WaterSense Final Specification for Flushing Urinals released in 2009. For supporting information on the specification, including background on its development, estimates of potential water savings, and the process for testing and certification of urinal products, read the 7-page statement from WaterSense.