Play Live Radio
Next Up:
Available On Air Stations
Watch Live

Making Use of 'Gray Water' During Drought

A California resident uses a hose to water plants May 13, 2008 in Berkeley, California.
Justin Sullivan
A California resident uses a hose to water plants May 13, 2008 in Berkeley, California.

A severe drought out West continues to threaten farms, fish, and water supplies to nearly everyone. Tighter water restrictions went into effect this month in much of Southern California, and the federal government issued a directive last week that could cut water delivery to farmers and residents in the state by 7 percent.

But some believe California is missing out on a key conservation method that's already available.

Susan Carpenter breaks California state plumbing code three times a week. Her accomplice is her washing machine. Rinse water from washing machines usually goes into the sewer — so what if you could recycle it? That's what Carpenter does, using it to water plants at her Southern California home.


"The washing machine is filling up with water, and it is going through its normal process of washing clothes," she says. "And after about eight minutes, you'll start to hear it spin and we will run outside and see it squirting through the tubes."

The "it" is gray water, which looks like its name — a bit gray, a bit cloudy. After all, it's the wastewater from bathtubs, sinks and washers.

The gray water lapping up Carpenter's dirty clothes will soon be lapped up by her passion fruit trees — and no, the fruit won't taste like Tide. She uses a special type of detergent that doesn't contain salt or boron, compounds which dehydrate plants.

"I spent about $350 on my system, and what I've saved in water is about a 100 gallons a week," she says

So how does Carpenter's system work? She's hooked up a valve that drains the water outside to a garden. Roughly one million residents in California use a similar type of gray water contraption. Some of them have been trained by Laura Allen, the co-founder of Gray Water Guerillas in Oakland.


"Currently, the codes are very restrictive and basically make sustainability illegal," Allen says. "So the kinds of systems we do — safe, simple, economical — … are accessible to most people."

California's code states that a legal gray water system needs to be nine inches under the ground. Those get-ups can be prohibitively expensive, costing up to $5,000 dollars. In Los Angeles, there are fewer than 10 residential permits. Gray water advocates want California to follow Arizona's model.

Arizona is the nation's leading example of permit free systems. There, a resident can use gray water as long as they follow a set of guidelines to ensure safety and no cross contamination.

Allen says this "frees up homeowners to be able to know they are doing the right thing."

What are the right guidelines for gray water? Sybil Sharvelle, an assistant professor at Colorado State University, is working on a five-year study that looks at the effect of gray water on soil quality and plant growth. She gets lots of requests from people looking for the results of the study.

"Most of the calls that I get are actually not just wanting a hint," Sharvelle says. "People are really applying pressure to get results and have us publicize the results that we have."

Those results won't be released until 2011, but California lawmakers aren't waiting. State Sen. Allen Lowenthal says California's Department of Housing and Community development is trying to come up with new rules.

"The emphasis is — as long as it is safe — to try to use gray water as a conservation tool in California and that is really where we are moving," Lowenthal says.

Back at Carpenter's house, the soapy water from the spin cycle has traveled through a PVC pipe and is shooting out of a black tube outside. Carpenter points out that it's sort of like cannibalism, "like whatever is you that is left gets eaten up by these microorganisms."

That could be the sign of what's to come as Californians and others in the West learn to grapple with news ways to use less water.