for National Geographic
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 U.S. Environmental Protection Agency (EPA) '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.
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 let in more water.
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."
What do you save?
By replacing 3.5-gallon toilets with 1.6-gallon or less models, the average family of four would save about 14,000 gallons of water per year.
How important is this?
The combination of population growth, increased use, and climate change are making fresh water a critical issue for our times. You won't save much money by saving water, but you will be making a big contribution to your community and to the planet—depending on where you live, wise water use may be the only way your region will continue to be habitable.
Showers are rife with opportunities for waste, thanks to the rise in popularity of multi-head shower systems, some of which spew an astonishing 80 gallons per minute (gpm). The bane of water conservationists everywhere, these multi-head showers end-run the federal standard that requires showerheads to pump out no more than 2.5 gpm by utilizing a dozen or more of the 2.5-gpm models.
What Do I Buy?
First, measure the water consumption of your current showerhead. Pour 2.5 gallons into a bucket, mark the water level, then empty it. Then, put the bucket under the shower and run the water for exactly one minute. If the water goes higher than the mark, get a new showerhead. There are low-flow showerheads of every type, ranging in price from less than $10 to $100 or so. And while you're at it, buy a 1.5-gpm aerator for your bathroom sink faucet. For less than $4, you'll save another few hundred gallons a month.
Water heaters: If major purchases are in your budget, consider a tankless, on-demand water heater. Households waste 6.35 gallons of water per day waiting for hot water, according to the Lawrence Berkeley National Laboratory, and 3.48 gallons of that is for showers alone. Tankless systems heat water when you need it, cutting wait times down to about 30 seconds and saving energy as well as water.
What Else Can I Do?
Change your expectations a bit. A water saving shower isn't going to be like standing under a warm Niagara Falls, but it will be nice and hot and get you clean. Keep a clean bucket in the shower to collect the water that runs while you wait for it to get hot (your houseplants or garden will thank you), and keep the whole process to 5 minutes or less. And don't succumb to the temptation to modify the flow restrictors in the 2.5-gallon showerheads.
How much do I save?
By replacing a 5-gpm showerhead with a 2.5-gpm model, you'll save 7,300 gallons of water per year. Cut your eight-minute showers down to five minutes, and you'll save another 2,738 gallons.
How important is this?
Using less hot water saves money, greenhouse gas emissions, and, of course, the water itself. This is a change well worth making.
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