Greywater: The Secret to Gardening During Drought

Guest Article by Molly Danielsson

It’s gardening season, time to water home-grown cucumbers and melons. Despite a cool July, much of Oregon is experiencing drought. Several streams are approaching record lows for this time of year. What’s a conscientious gardener to do? Rain barrels can collect rainwater from roofs for the garden (and EMSWCD can help hook you up), but here in Oregon rain is often lacking when we need it the most.

Luckily there’s already a consistent source of water available in your house: greywater. Greywater is the used water from sinks, showers, or washing machines. It never includes waste from toilets—that’s blackwater. Plants don’t mind the little bits of food and dirt or trace of soap in greywater as long we take care to avoid using products with boron, chloride and sodium.

Businesses and houses anywhere in Oregon can set up systems to reuse their greywater for watering their plants by getting a permit from the DEQ or redirect greywater to use for flushing toilets or cooling mechanical systems by getting a permit from the plumbing department.

Oregon is one of just five states that has a tiered approach to permitting greywater. This progressive approach means a household generating less than 300 gallons per day of greywater will find it simpler and easier to get a permit than a building making 1,000 gallons per day. That means the average homeowner won’t face red tape when they want to do the right thing. That means that for only $50 you can get a permit for a simple outdoor greywater reuse system for watering your trees.

Oregon is on the cutting edge of water conservation because community members came together with Recode – an organization that works to ensure access to and accelerate adoption of sustainable building practices – and the wider green building community to ask for scaled solutions for this readily available resource.

If you’re curious check out Greening Your Garden with Greywater, a free workshop Recode has helped organize in Portland on August 13.

To date only 26 households have gotten permits to reuse greywater for watering their yards and even fewer for indoor reuse. Recode’s research has, so far, found only four commercial projects in Oregon that have reused greywater for indoor purposes: the First Alternative Co-Op in Corvallis and three in the Portland area: People’s Food Coop, Bud Clark Commons, Hassalo on Eighth and Nike’s upcoming Beaverton Campus. (If you know of others let Recode know! Email:


If Oregon has progressive greywater and stormwater reuse regulations and a population interested in water reuse, what’s holding us back from having every home and office’s wastewater beautifully reused? One possible reason is that the relatively low cost of water lowers our motivation for reuse. According to the National Academies of Sciences, Engineering, and Medicine Report on Using Greywater and Stormwater to Enhance Local Water Supplies: An Assessment of Risks, Costs, and Benefits, even the cheapest greywater reuse systems, a simple laundry-to-landscape greywater systems, offer a payback period of 2.5-6 years. That’s pretty good, but costly enough to discourage some owners.

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A laundry to landscape system can cost $150-250 in parts, $700-$2,500 for a professional installation.

Organizations like EcoDistricts and the International Living Future Institute point out that water systems often work best when planned on a district or multiple building scale, yet that is exactly where regulations are unclear. Projects like the Code Innovation Database and Recode are working to provide more information about the costs and benefits of these innovative projects to help both consumers and jurisdictions that aren’t yet regulating greywater learn from other’s experiences.

The good news is that the research shows that greywater reuse offers substantial water savings and is a consistent source of water for dry areas. Los Angeles currently meets its water needs with 11% coming from local greywater and plans to increase that to 16% by 2035. They also noted that greywater reuse for households in areas like Los Angeles and Seattle have a potential for more water savings than stormwater reuse, since stormwater is only available as a water source when it rains.

Here in Oregon we’re lucky enough to already have progressive water regulations, so get out there and install a greywater reuse system in your backyard! The researchers made a call for more research and information sharing on best practices and costs for greywater systems. Recode and Code Innovations Database is answering that call this fall by sharing information from lessons learned from greywater projects in Oregon. Together with our partners Recode is working to ensure regulations keep pace with research.

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