Question and Answer

QUESTION:  I know that some of the cities use recycled water for irrigation. Can I do this at my home?


ANSWER: Graywater. Doesn’t sound all that appetizing does it? Well, it’s not meant for drinking. Graywater is a largely unutilized alternative to using virgin “blue” water for irrigation. This is the mostly soapy water that drains from our showers, sinks and washing machines (must not be contaminated with toxic cleaning products or soiled diapers). Normally this graywater ends up with the sewage flushed from toilets and heads to the wastewater treatment plant. But there are relatively easy ways to keep your graywater separate from “brown water” and filter it so it can be used for irrigation. It would be great to see more homes taking advantage of this resource, because the majority of residential water use is for landscaping. Unfortunately, until recently it was all but impossible to get a permit to install a residential graywater system here in Sonoma County. The same is true in many California counties.

Graywater use is legal in California and relatively common in the industrial sector, but creating a residential system that conforms to the state’s complicated plumbing code tends to be time and cost prohibitive. In May, the first legal, fully-permitted household water reuse system in Sonoma County went online in Petaluma. Trathen Heckman, founder of Daily Acts, which leads a number of green living tours throughout the North Bay, was granted the permit for his home. A civil engineer volunteered to work with Heckman to create a model system that would show city officials and water customers that residential graywater systems are a viable and safe option. Heckman’s wash water now flows through a simple network of pipes into a constructed wetland (i.e. an underground gravel-filled trench enclosed in a waterproof liner) that filters the water before it is distributed to the roots of edible plants and shade trees. The average four-person household in Petaluma uses more than 100,000 gallons of drinkable “blue” water a year. Heckman’s system has the capacity to funnel 36,000 gallons of once-used water into his backyard for a second use.

Graywater is just one form of recycled water. The recycled or reclaimed water that cities produce undergoes more treatment and disinfection than at-home graywater, and can be used for a wider range of irrigation. Napa Sanitation District has an aggressive recycled water program.  Over the past 5-years Napa Sanitation has recycled an average of 651 million gallons of water per year (that’s about the same amount of potable water that Napa used in June). The recycled water is purchased by golf courses, vineyards, industrial parks and cemeteries.  They plan to expand their capacity over the coming years to reuse as much of this valuable resource as possible.  In addition to Napa Sanitation District, the cities of St. Helena and Yountville also have recycled water programs in place.