Gray water grows a garden
The next time you rinse vegetables in the sink or put last night’s plates in the dishwasher, consider that residential kitchens across California are sending, according to an estimate by Oakland’s Greywater Action, 260 million gallons of water down the drain every day. Ouch. That waste bothered writer and environmentalist Jennifer Nix so much that when she and her husband began remodeling their Sausalito home recently, she not only created a movable kitchen unit called the Go-go Kitchen — a cabinet-and-appliance system made from salvaged and recycled materials — but also tinkered with the plumbing to install a simple system to send water from their kitchen to the garden.
Never mind that the re-use of what is known as kitchen gray water — untreated waste water — is illegal in California. (The use of gray water generated by shower and home laundry machines is allowed, with certain restrictions.) Unable to get a permit from the city or Marin County, Nix forged ahead, using methods employed in the state of Oregon, where kitchen gray water use is legal. (It’s legal in Washington state, too.)
“I may get red-tagged, I may get fined — that’s OK with me,” Nix said. “There are many people doing this because it’s the right thing to do.”
On the other side of her Gogo Kitchen, designed by Nix and artist friend Jeff Smith (the custom units are made by her ModNomad-Studio), are pipes in her home’s walls that bring clean water into the sink and take the gray water out.
The mechanics are simple: A joiner piece has been hooked to the city line on one side and the garden pipe on the other. A diverter valve was installed in the plumbing under the house, as was an actuator connected to an electrical line that goes through the house walls to a switch in the kitchen. With a flick of the switch, the diverter sends outgoing water to the yard or to the sewer, depending on whether Nix thinks the water is too greasy for the plant bed.
Nix said she followed the state of Oregon’s regulations for kitchen gray water re-use, creating an outdoor trench lined with bark chips covered with mulch. Gray water flows into the trench, which bisects the garden, and the wood chips filter organic matter or harmful bacteria (from raw meat, poultry or fish) before the water seeps into the ground (a form of treatment in which organic matter and bacteria die and break down). The chips are replaced once or twice a year.
While Nix is flouting the law a bit, she’s part of a movement to make the use of kitchen gray water not only possible but standard.
Oakland’s Greywater Action, a leading conservation group that provides information about simple rainwater and gray water re-use systems (www.greywateraction.org), has been working to change the laws surrounding kitchen gray water use.
Kitchen gray water is not allowed to be reused in California because of the high amounts of fat and food waste that can be mixed in the water. Studies
have shown that wastewater from kitchen sinks may contain concentrations of fecal coliform similar to what’s found in a toilet, said Andrew di Luccia, a spokesman for the California Water Resources Control Board, who noted that Oregon and Washington require kitchen gray water undergo treatment first.
Laura Allen, a co-founder of the group, said initial efforts targeted the state plumbing code. But that proved fruitless: What’s needed is legislation to change the California Health and Safety code’s definition of gray water, she said. Allen has been unable to find a sponsor.
Most indoor water is used for toilets and laundry — from 45 to 70 gallons a day per person, depending on the efficiency of the appliances, Allen said. Some 35 percent of the outflow is gray water, with the rest considered “black water” (toilet water) unsuitable for re-use.
Though kitchen gray water systems are illegal here, there’s no prohibition against putting a bucket in your sink to catch rinse water and manually dumping it on plants or lawns, Allen said, because the water hasn’t gone into the plumbing system where it would be covered by code.
When doing so, use plantfriendly soap and avoid storing such water in drums.
“I would strongly discourage using a barrel,” Allen said. “It gets really gross because the organic materials in it decompose.”
As the drought continues, it’s not just Nix who is looking to recycle.
Brent Helm, an engineering contractor who runs Cal Water Solutions in Berkeley, specializes in installing rainwater and gray water systems and said his business has nearly tripled, from 10 projects in 2014 to 30 projected for 2016.
“People feel guilty about draining their tub after taking a bath,” he said.
With his degree in hydraulics and hydrology, Helm builds flood-control systems as well as water conservation plans. Clients often ask about kitchen gray water recovery, and he is obligated to tell them that he cannot legally install a system, even for vegetarians who don’t eat meat, poultry or fish and who do not have a garbage disposal unit flushing groundup food bits into the pipes and outdoors.
“My license,” he said, “is on the line.”
It doesn’t stop him from telling the clients how to do it themselves, though.
A gray water do-it-yourselfer could, with some basic training and plumbing and construction skills, install a basic gray water system in a home for $300 to $500, he said.
Nix, an optimist, hopes that more people will roll up their sleeves and join her, noting, “It’s hard to fault people who are on the right side of history and the common good.”