High-efficiency water saving toilets (HETs), are defined by the WaterSense program of the U.S. Environmental Protection Agency as using less than 1.3 gallons per flush (gpf) and performing as well as - or better than - conventional, less efficient models.

That flush volume represents a 20% reduction over conventional models.

Two types of HETs are available:

• Single-flush models that use 1.3 gpf or less, delivering the water savings required to earn WaterSense certification.
• Dual-flush models allow users to choose either of two modes: the standard 1.6 gpf for solids or 0.8/1.0 gpf for liquid waste.

Things to look for:

• The WaterSense label. It assures users that water saving toilets will perform as well as - or better than - conventional, less efficient models.
• MaP Test Score. The WaterSense-certified Cadet 3 FloWise from American Standard achieved the maximum, bulk removal flush rating of 1,000 grams (more than two pounds) in MaP tests by an independent testing organization. Cadet 3 FloWise can move a mass 60% larger than standard bowls.
• Generously wide waterways. Most toilets have a 2-inch wide trapway, through which the contents of the bowl are flushed to a drain beneath the fixture. Featuring an oversized 3-inch flush valve and a 2-1/8-inch trapway, the aforementioned Cadet 3 FloWise from American Standard offers the widest trapways available, and is able to move a mass 60% larger than other water saving toilets with smaller trapways. A fully glazed trapway facilitates complete clearing of the bowl.
• In dual flush toilets, go siphonic, not washdown. Siphonic dual flush toilets have an exclusive, patented quiet jetted Power Rim Wash that completely scours the bowl with each flush, ensuring a virtually clog-free flush using at least 20 percent less water than today's toilets. They also have a much larger area of water in the bowl-called the water spot-than other dual flush toilets, reducing streaking and staining in the bowl.