Energy & Environment

Shades of Greywater

Laura Allen is no one's idea of an unrepentant lawbreaker. But under California's state plumbing code, that's exactly what she is. Allen, a soft-spoken elementary...
by | April 30, 2009

Laura Allen is no one's idea of an unrepentant lawbreaker. But under California's state plumbing code, that's exactly what she is. Allen, a soft-spoken elementary school teacher from Oakland, likes to sprinkle her garden with water from her washing machine--something state law allows only under very limited circumstances. She's also a member of a group that publishes do-it-yourself guides on how to circumvent strict water laws around the country. They're called the Greywater Guerrillas.

Greywater refers to effluent from showers, bathroom sinks and washing machines. (It does not include the more hazardous wastewater that comes from toilets, kitchen sinks and dishwashers.) Unless you enjoy a cool glass of soap, greywater isn't good to drink. But advocates such as Allen argue it is safe to use for other purposes, especially outdoor irrigation. To do otherwise, she says, is to flush perfectly good water down the drain.

Allen and a couple of housemates became scofflaws years ago, when an outrageous water bill inspired them to rig their plumbing to capture and reuse water. Before long, the housemates founded the Guerrillas. As it turned out, lots of people around the country were interested in water recycling, too. "Some people are doing it for environmental reasons," Allen says. "Some people live in areas where the wells are drying up, some people just want to save money."

Now, the Guerrillas and other greywater advocates are taking their fight to state capitols and city halls. They want regulators to loosen plumbing codes that assume all wastewater flows straight to the sewer or septic tank. And they have a model for how to do it. Arizona now allows residents to install greywater systems without a permit, provided they use 400 gallons or fewer a day and meet certain performance standards. The city of Tucson has gone a step further. Last September, the city approved a regulation that, beginning in 2010, will require all new homes to include plumbing that enables greywater systems.

Similar laws are less likely in cold-weather climates where pipes freeze in the winter. But in the South and West, where populations are growing and water supplies tightening, increased household water reuse is a real possibility. New Mexico and Texas have approved laws similar to Arizona's. Now, California is looking at relaxing its rules, too. For greywater advocates, the change not only would legitimize plumbing work that thousands of people have done on the sly. It also would encourage others to install greywater systems--and make professional plumbers comfortable with taking jobs they otherwise can't touch without a permit.

An even bigger boost may be on its way in the next few years. The trade association that writes the Uniform Plumbing Code--a document that many states and localities defer to in their own codes--is looking at loosening rules for greywater and other alternative water sources. "We know the code is not where it should be," says Dave Viola, who is overseeing the effort for the International Association of Plumbing and Mechanical Officials. "We're trying to catch up."

Ever since the invention of indoor plumbing, conservationists have been looking for ways to use their water more than once. They've come up with all manner of ideas, some complicated and others quite simple. For example, in Arizona, it's not uncommon for people to put a washing machine on the back porch, and allow the used water to flow out to the yard or garden.

That's not the best way to set up a greywater system, Allen says, but it's close. Those washing machines, she suggests, could have their hose at back attached to a three-way valve. Then the valve could be turned, depending upon the preferred destination for the wastewater. Need to water the flowers? Send the water to a tube that leads to a garden. Don't need to reuse any water today? Channel the waste back to the sewer system. It's possible to create more elaborate systems--pipes, after all, can go anywhere. But even the Guerrillas have their limits. For example, they don't recommend rigging toilets to flush with water from the shower. That's because greywater can corrode sensitive parts of the toilet.

What concerns regulators more is safety: Is it really OK to reuse water mixed with soap, shampoo and everything else that goes down the drain? Greywater advocates say the answer is yes, with a few caveats. Creating a pool of standing greywater outside is a no-no. So is cleaning soiled diapers in the washing machine and then sending the effluent out to the garden. Even when those things happen, however, advocates say there's virtually no risk of anyone getting sick from it. The evidence is that thousands of rogue greywater users have been bending the rules for years, apparently without incident. Bahman Sheikh, a California-based consultant who has studied the safety of greywater, says regulators have been too cautious. "They are going for zero risk," he says. "That's ridiculous. Zero risk is extremely expensive when you think of water as a valuable resource."

Regulators, though, make no apologies for playing it safe. Officials leading the rewrite of California's greywater rules say they haven't seen any long-term studies of greywater safety. The nonprofit Water Environment Research Foundation is conducting just such a study now. When it's published in 2011, the study should provide greater clarity about the question of health risks.

In Arizona, the debate has moved beyond safety and into economics. Even before the greywater issue came up, Arizona was recycling wastewater on a more industrial scale. For years, golf courses, parks and schools have kept the grass green using treated but nonpotable water processed at reclamation plants. (This is called "purple water" for the purple pipes signaling not to drink it.) So as the debate is unfolding in Arizona, it can sound a bit like making a choice between crayons: Do you like your wastewater grey or purple?

Phoenix prefers purple. Ray Quay, assistant director of the city's Water Resources Department, worries that if homeowners use up greywater in their own yards, they won't send the city enough water to treat and pass on to its purple-water customers. "If people use greywater inefficiently," he says, "that's actually wasting water because that water would have gone back into the system."

Greywater supporters bristle at this. They think citizens should reuse water upfront, rather than counting on utilities to do so later. They note that water treatment facilities are expensive and require a lot of energy. And, they point out that individuals can save money by using less water. With purple water, the utilities are the ones that stand to profit.

According to Quay, Phoenix doesn't prohibit residents from using household wastewater but doesn't encourage it, either. Tucson, by contrast, thinks grey is golden. The requirement for greywater plumbing in new homes won approval after city officials reached a deal with homebuilders, who were initially skeptical. Homeowners won't actually be required to use the systems. But the hope is that by having the plumbing already in place, residents will find it simple and convenient to give household water recycling a try. "We wanted to make water conservation the rule," says Tucson City Councilman Rodney Glassman, "rather than the exception."

The Color of Suds

Greywater: Effluent from showers, bathroom sinks or washing machines, which most experts believe to be safe for watering plants and other nonpotable uses.

Black water: Effluent from toilets, kitchen sinks or dishwashers, generally not safe for household reuse.

Purple water: Wastewater treated at a reclaimed water plant, suitable for watering crops and golf courses but not for drinking.

Josh Goodman
Josh Goodman  |  Former Staff Writer

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