Gray-water gardening

From slavery to strip-mining, history is full of ethical and ecological missteps that seem ridiculous with the benefit of hindsight. With issues of water usage and conservation becoming more pressing, it’s likely future generations will look back at the way we use water with shame and disbelief.

According to the United States Department of Agriculture’s website, California households commonly use between 163,000 and 326,000 gallons of water per year, with individuals using anywhere between 50 and 300 gallons a day.

Residents of Chico’s GRUB Cooperative are taking a giant gulp out of their water consumption by using a gray-water washing machine system built by GRUB members Tim and Stephanie Elliottt. The Elliottts and their 8-month-old baby, Collin, share a large south-Chico home with 15 housemates. Their gray-water system diverts water used for laundry—which can equal about 40 gallons per load, considering the size of laundry loads in the busy household—to water their garden and landscaping. (Newer, energy-efficient machines use about half that much water.)

Gray water is water from sinks, showers, tubs or laundry that doesn’t come into direct contact with potentially unhealthful waste, such as human feces. Though it may contain material not suitable for human consumption (hair, grease, household cleaners, etc.) and may look somewhat dirty, it can be used for irrigation.

Especially given the current climate of concern around the use of water—global warming, drought, over-tapping of wells and aquifers for such things as watering lawns and operating large water-bottling plants—conserving water seems like a smart idea.

“We took part in a workshop in the Bay Area offered by [sustainable-water action group] Greywater Guerrillas,” Tim said of the sliding-scale workshop that cost attendees from $50-$100. “These two women run it—one is a schoolteacher and one is a plumber—and they have been doing the same workshop for over 10 years.

“It was very hands-on,” he continued. “When we got there [to the Oakland home hosting the workshop], the house didn’t have a gray-water system, and before we left that day we did the first load of laundry.”

To expand the educational value of the project, and in keeping with the old proverb of teaching a man to fish, the Elliottts installed their system the same way—by hosting a workshop.

“We had about seven or eight people from the community here,” said Tim, “and when Stephanie and I put it together, we showed them as we were doing it.”

They have also helped another local couple put a similar system in place and said they’re willing to do more workshops if people are interested in a gray-water laundry system in their own homes.

“The way it works is the water that comes out of the washing machine used to go straight through a tube into the sewer,” Tim explained. “We installed this switch right here so it can either go straight to the sewer or be used for gray water. When it’s switched to gray water, it goes through a different tube and underneath the house, and then there’s a bunch of PVC pipe that carries it outside to water our plants.

“Plumbing-wise,” he continued, “it’s really easy to install. The stuff was all easy to put together and I just had to drill a hole in the floor. The most painful part was having to crawl under the house to place the PVC pipe.”

The Elliottts obtained the necessary materials locally from Collier Hardware, Park Village True Value Hardware and Chico Sprinkler Inc., and from PlumbingSupply.com, for a total cost of $132.

Outside the house, the water runs through hydroxy-terminated polyether (HTPE) pipe to two separate tiers, and a simple valve is turned to determine which level gets the water.

“Because of the amount of plants we have, how much traffic we get on this one machine and the drop [in land elevation] we have available, we decided to put up two different tiers,” Stephanie said. One tier is roughly level with the house, while another hose runs down about a foot to another group of plants. The two-level system assures that each level is not over- or under-watered. “Either we or the housemates switch the tier every five loads.”

Maintenance thus far has been easy, according to Tim. “Since this machine gets a lot of use,” he offered, “we have to take off a few pieces and remove all the lint every six months or so, but in a regular household you’d have to do it much less often.”

With the exception of a few pieces of pipe and the switch, the system looks and operates just like a normal washer with a few added concerns.

“With our baby, when we do loads of poopy diapers we don’t want it to run out here [to the garden],” Tim said. “You do want to be aware of what you’re washing because you don’t want human or animal waste going into it.”

Stephanie advised that watering most vegetables with gray water is fine, with the exception of root crops such as carrots or beets. “No veggies that come in direct contact with the water,” she explained, “but tomatoes or other vegetables, or ornamentals, are just fine.”

Stephanie’s advice is echoed by gray-water advocate Allen V. Barker, professor of Plant Science at the University of Massachusetts, Amherst, who advises (at www.umassgreeninfo.org) that one “restrict its application to the soil around plants such as corn, tomatoes, broccoli, or other vegetables of which only the above-ground part is eaten. Do not apply gray water to leafy vegetables or root crops.”

Also, normal, name-brand laundry soap is not suitable for gray water used for gardening.

“There are certain kinds that are more compostable and nicer to plants,” said Tim. At the GRUB house, the residents use Bio Pac concentrated liquid laundry detergent, a biodegradable, perfume- and dye-free product that is available in bulk at Chico Natural Foods. Stephanie noted that Bio Pac was formulated by an expert on gray-water systems.

She said they also considered converting the showers and sinks in the bathroom to gray water, but the galvanized piping used there is not as easy to cut into.

“We’re looking into doing more, though,” she said. “Hopefully we’ll get at least another sink out of it.”