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From our toilets to our tubs, roughly 60 percent of a home's water consumption takes place in the bathroom, according to the California Urban Water Conservation Council. So if you have an eye on water use, start here.

What Do I Buy?

Water-Saving Toilets
Guzzling 27 percent of your household supply every year, your toilet is by far your home's largest water user. The Federal government now mandates that new toilets use no more than 1.6 gallons per flush, but older toilets can use two to three times that much. And even the new ones will use more if you don't maintain them.

When buying a toilet, look for the Environmental Protection Agency's WaterSense label. To receive the label, toilets must be independently tested to show that they use, at most, 1.28 gallons per flush (gpf). Dual-flush toilets, those that have a full-flush mode for solids and a reduced-flush mode for liquids, use 1.6 gpf and .8 gpf respectively. And if you want to go as green as possible, there are composting toilets, which break down human waste into a nutrient-rich material that can be spread around trees and non-edible plants. See our Toilets Buying Guide for suggestions.

What Else Can I Do?

Maintain the toilet you've got.
A 2000 study commissioned by the city of Tucson revealed many 1.6-gallon toilets had been modified by homeowners or plumbers: "early-close flappers," devices that prevent the water tank from releasing more than 1.6 gallons, had been replaced with standard 3.5-gpf flappers, and dams, which also prevent a 3.5-gallon tank from releasing more than 1.6 gallons, had broken or were intentionally removed.

If you've moved into a home with a 1.6-gpf model, there's no way of knowing whether the previous owner made any such inefficient modifications. As the parts wear out—they generally last around five years—be sure to ask specifically for 1.6-gpf replacements.

Most older homes (pre-1992) still have 3.5-gpf toilets. If yours does, you can reduce the water it uses by filling a milk jug with stones and placing it in your toilet tank to displace water. But be wary of toilet-tank retrofits, kits designed to convert old 3.5-gpf models into 1.6-gpf toilets, says Gary Woodard, co-author of the Tucson study. "You're doing something to the toilet that it isn't really designed for," he says. "It's really best to get a low-flow toilet."