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On Conservation: Even your water can be reused

Monday, July 11, 2011

By Alex Keller, EWG Summer Water Analyst

When I was growing up in Pennsylvania, my mother used to admonish me to conserve water during droughts. "Turn off the faucet while you brush your teeth," she'd say, "and take a shorter shower." Most people have heard this advice. But is it the most effective way to reduce water use?

This might come as a surprise, but fully half of home water use occurs outdoors. Watering a garden, lawn or those new trees commonly requires more water than washing the day's dishes, doing a load of laundry or taking an entire family's worth of showers.

Deconstructing home water use Research by Colorado-based water engineering firm Aquacraft has found that 46 to 59 percent of residential water consumption goes on outdoors. In summer, a time of intense lawn watering and (naturally) heaviest water shortages, outdoor use claims up to 78 percent of the total.

That's a lot of water out of the hose.

As one would expect, research has shown outdoor water use to be strongly tied to climate. A lawn of turf grass in an arid region, of course, needs more watering than the same lawn in a wetter area. Those hot, dry areas tend to have a lot of swimming pools, as well - another water hog.

Ironically (and perhaps tragically), the places using the most water outside are the places that often have the least water to spare. People in the arid Southwest use 59 to 67 of their scarce water outdoors, compared to only 22 to 38 percent in cooler, wetter regions.

The good news is that there are efficient methods to irrigate lawns and gardens.

Treated water for you - and your plants? If you draw your water from a municipal utility rather than a well, all the water piped to your home has been treated to drinking water quality -- at a significant cost to ratepayers. When we spray treated water on lawns and golf courses and pipe it through the toilet, that's overkill.

Researchers and water conservation departments say that much of the water we use inside, depending on its first use, can be recycled for certain forms of irrigation as what is commonly known as gray water.

Gray water is a win win In a 2010 study, the U.S. Environmental Protection Agency and Water Research Foundation estimated that gray water reuse systems can save at least 30 percent of total household water consumption. Yet the same study found that only 7 percent of American households are using these systems. Even in California and Texas, the two states where gray water technology has gained greatest acceptance, fewer than 15 percent of households have installed such systems.

Gray water is a promising concept popular with smart growth advocates around the globe because it offers immediate savings. Municipal utilities encourage gray water systems because they ease pressure on the water treatment plant and reduce wastewater. Homeowners can offset the installation costs of gray water systems with lower water bills - a definite plus these days - and guiltlessly enjoy outdoor plants, even in arid regions.

Sound like a good idea? Come back soon for our next blog in which we take a look at some of the laws on gray water use in different states and assess different ways household water can be reused.

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