Cover art from the San Francisco Graywater Design Manual

Going gray

The summer heat is on, and you're watching the water bill climb. You'd like to conserve water — and your landscaping, too But beyond watering early in the morning and planting drought-tolerant natives, what else can you do?

It may be time to go gray.

Graywater is household wastewater diverted from one of four sources — washing machines, bathtubs or showers, bathroom sinks and kitchen sinks — and reused as irrigation water. Up until very recently, graywater reuse was not legal in Oregon.

In 2009, following the lead of several other states, the state Legislature passed a bill directing the Department of Environmental Quality to set standards and create a permit structure for graywater reuse and disposal systems. The agency completed this process in 2011 and began issuing permits last spring.

"It's state policy to encourage graywater reuse," says Ron Doughten, DEQ's Water Reuse Program coordinator. This includes holding educational workshops, and the first was held in Ashland in June.

DEQ has tried to make the process simple and inexpensive. The agency has defined three types of graywater and created a tiered permit system to accommodate different needs.

Type 1 graywater is untreated, although it may be filtered to remove grease, hair and food particles. It must be discharged at least 2 inches below the soil surface and cannot be stored for more than 24 hours. Type 2 graywater is filtered and chemically or biologically treated to reduce suspended solids and organic matter; it may be stored and used in above-ground, drip-irrigation systems. Type 3 graywater is Type 2 graywater that also has been disinfected.

"Oregon goes further by expanding use of graywater beyond subsurface irrigation," says Doughten. However, most homeowners probably will opt for the simplest (and least expensive) Tier 1 permit.

A system must produce fewer than 300 gallons of Type 1 graywater a day to qualify. (To put this in perspective, the average home produces between 90 and 110 gallons daily.) When deciding which fixtures to tap, consider the consistency of the source along with the volume and quality of the graywater it produces.

"Accessibility of plumbing is also an issue," says Doughten. "For existing homes, you're going to see the greatest benefit with so-called 'laundry-to-landscape' systems."

A washing machine is the ideal graywater source: Each load produces between 15 and 40 gallons of water, and most households wash a predictable number of loads per week. Unless you're washing soiled diapers or using harsh chemical detergents, the resulting graywater is safe and relatively clean. A kitchen sink, on the other hand, yields a lower volume of "dirty" graywater, often containing grease and oils, solid particles and organic matter. Dishwashers, garbage disposals and toilets are not acceptable sources of graywater.

For laundry-to-landscape systems, determining typical weekly graywater output is simple. If a washing machine uses 20 gallons per load and typically does three loads per week, count on 60 gallons of graywater weekly. Estimating irrigation needs is trickier, but formulas available on DEQ's website can help.

Graywater can be used on trees, landscaping plants, compost, lawns and gardens — everything except edible root crops such as carrots and beets. There's another advantage to tapping the washing machine: The system uses the washer's built-in pump to move graywater.

The city of San Francisco's "Graywater Design Manual" recommends using 1-inch polyethylene tubing to distribute graywater to "mulch basins" around trees, which helps prevent runoff. No matter which fixture you tap, you must install a three-way valve that allows either diversion of graywater to landscaping or release to the sewer system.

"Know your soils, know your plants' water needs and only use graywater when you need it," says Doughten.

Homeowners will have to adjust the amounts of graywater they use as the seasons change. Our wetter Southern Oregon winter probably doesn't require any at all.

Whether the system is simple or complicated, it involves some costs. The Tier 1 permit from DEQ costs $90. This includes a one-time fee of $50 plus an annual fee of $40. DEQ will waive this fee four out of every five years if permit holders provide simple, yearly reports on their systems.

Then there are materials and plumbing permits.

"Once you make a physical alteration to plumbing, you'll need a plumbing permit," says Doughten. A homeowner probably won't need one simply to install a three-way valve at the pipe that drains a washing machine.

Because graywater systems have been legal for only a short time, there may be a shortage of local examples on which to model one. Doughten recommends the San Francisco's free guide, available at www.urbanfarmerstore.com/library/pdf/general/sfgraywaterdesignmanual.pdf

Also look for "Laundry to Landscape: A Simple, Efficient, Economical, Easy-to-Use Greywater System," an instructional DVD by Art Ludwig.

So will you start saving money immediately? Yes, although, it may take awhile for a graywater system to pay for itself.

"We calculated water savings for four different communities across the state," says Doughten. According to the study, reusing graywater can save a household between $27 and $71 annually, and it also saves water and energy, resources that are only going to become more precious — and expensive — in the future.

"People are recognizing the need for alternative sources of water," says Doughten. "And 60 percent of household wastewater comes from graywater sources."

Learn more about state standards for graywater systems and download permit applications at the DEQ Water Reuse Program website: www.deq.state.or.us/wq/reuse/graywater.htm

Juliet Grable is a freelance writer living in Ashland. Reach her at julietgrable@yahoo.com.

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