What to Look For

Toilets account for 26.7 percent of water consumption in the home, and older models use far more water than newer designs. If the bathroom fixtures in your home were installed prior to 1992, replacing your toilet with a more efficient one could save thousands of gallons of water annually, between 14,000 and 25,000 for a family of four.

Gallons per Flush

Toilets are rated based on their gallons per flush (gpf). Low-flow toilets, using 1.6 gpf or less, are now the federal standard. High-efficiency toilets use 1.3 gpf, and others use as little as 1.1 gpf. Dual-flush toilets have two gpf rates (solids are flushed at the higher 1.6 gpf rate, while liquids use 1.1 gpf or less), and composting toilets use no water at all.

EPA WaterSense Rated

The EPA's WaterSense label requires toilets to be independently tested to show that they use, at most, 1.28 gpf and that they can successfully flush 350 grams of test media. Dual-flush toilets, those that have a full-flush mode for solids and a reduced-flush mode for liquids, must use 1.6 gpf and .8 gpf respectively (the combined average flush rate for these toilets is 1.28 gpf).

Maximum Performance (MaP) Testing

Maximum Performance Testing is a collaborative program between the Canadian Water and Wastewater Association and the California Urban Water Conservation Council, which tests the ability of a toilet model to completely remove solids in a single flush. The program determines the maximum amount, in grams, that a model can effectively remove, and recommends that all models be capable of removing at least 250 grams of solids

Shopping Tips

• Composting toilets contain and control the composting of human and household waste using little or no water at all, saving you the nearly 30 percent of household water generally used to flush toilets. The trade-off with composting toilets is that some require energy, while traditional toilets use none at all. A Texas state government analysis found that some models use 2 to 3 kilowatt-hours per day.

• High-efficiency toilets are often sold in two parts. When shopping, be sure that the model numbers on the tank and the bowl match.

Usage Tips

• Don't use your toilet as a trash can. Toss dead bugs and tissues into the land trash.

• Fix leaks. Toilet leaks can cost you up to 200 gallons of water each day, the same amount it would take to wash 10 loads of clothes in an Energy Star-rated washing machine.