By Greg Richardson
In the United States, indoor residential water use is estimated to average about 70 gallons per person per day, which is the highest of any country in the world. By incorporating water-efficient strategies into a building’s design, you can reduce this number substantially without requiring unwanted lifestyle changes. The following graph — based on numbers found in Rocky Mountain Institute’s “Water Efficiency: For Your Home” report — identifies where the greatest water use takes place in a home and indicates how to design for water conservation effectively.
Toilets
Toilets and toilet leaks use more water than any other appliance in an average home and are generally responsible for over 40,000 gallons of water use per year. To be really efficient low-flow, composting, and dual-flush toilets are available that will conserve tens of thousands of gallons of water annually. While composting toilets may be out of the question for many people, the U.S. Environmental Protection Agency offers a list of water-efficient toilets. An even more innovative technique is to use a greywater system, like the AQUS, that allows you to flush the toilet using water from the sink and/or shower.
Washing Machines
Washing machines are responsible for over 20% of home water use, but those that have front-loading doors use about 20 to 25 gallons of water per load, whereas traditional top-loading models use about 45 to 60 gallons. By using less water per load, these machines also require less detergent and energy, as well. See a list of some of the best water-saving washing machines.
Showers
Water-efficient showerheads used to be notorious for their unsatisfying, low-pressure wash; however, technological improvements allow new showerheads to maintain strong pressure while halving the flow rate. Considering that such showerheads range between $15 and $50, they are a very cost-effective investment.
Sinks
By mixing air into the water stream, sink faucet aerators make it possible to reduce water use significantly. Without lowering pressure levels, aerators can reduce water flows to between 0.5 and 2.0 gallons per minute (gpm) as opposed to the more conventional rates that fall between 3.0 and 7.0 gpm. Note that kitchen sinks require greater water power, so flow rates closer to 2.0 to 2.5 gpm would be more appropriate. Fortunately, sink faucet aerators are very cheap and screw easily onto existing faucet heads. See a list of the most efficient 2008 sink faucet aerator models.
Dishwashers
Surprisingly, dishwashers account for a small fraction of home water use. Modern dishwashers now use about six to eight gallons per cycle, and those with ENERGY STAR® labels generally use closer to four. Therefore, the art of water conservation relies more on how to use a dishwasher efficiently. See a list of water-efficient dishwashers.
Other
There are other, more advanced water conservation strategies that can be integrated into your building’s design. Click on the following links to learn more about greywater systems and rainwater harvesting.
The United States Environmental Protection Agency has also developed a WaterSense labeling system (similar to that of ENERGY STAR® )that will certify homes as water efficient as early as 2009.
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