When Is the Best Time to Install a Greywater System?

The Answer is Now!

By Rachel Trachten


A Water Champions team installs a plume pipe to feed greywater to this garden from below the surface. (Photo courtesy of Water Champions)

When Ayse Sercan was training as an architect, the topic of greywater came up frequently. “We talked about the fact that we waste a lot of water that’s perfectly usable just because it’s a little bit used,” says the Alameda resident. “I wanted to see what the benefits of greywater could be, and I was willing to experiment on my own house.”

Greywater is the gently used water from washing machines, bathroom faucets, showers, and bathtubs that can be captured, filtered, and reused. Not considered greywater would be water from toilets or water used for washing diapers; likewise, water from kitchen sinks is not termed greywater in many states including California.

There are many ways to introduce greywater systems to your own property depending on your budget and landscaping needs.

Start with ‘Laundry to Landscape’

“I encourage people to start with the washing machine and figure out which portion of the landscape they can irrigate with that laundry water,” says Laura Allen, a founding member of Greywater Action, an educational collaborative that teaches residents and tradespeople how to reduce household water use. The Laundry to Landscape (L2L) method was invented in 2008 by author and ecological systems designer Art Ludwig, who published his online guide unpatented and into the public domain for the common good.

“Look at your landscape and start with your biggest plants, the trees; they’re easiest to get the water to,” says Allen. “Greywater is excellent for fruit trees, shrubs, berries, and other large plants, but shouldn’t be used on edibles if it would directly touch the food part, for example, a carrot.”

In her Alameda home, Sercan started out in 2008 with a simple L2L system, which draws on water from the hose at the back of the washing machine and doesn’t require a special tank or filter. As the washing machine pumps water out (at between 7 and 26 gallons per load, according to Consumer Reports), a diverter valve directs the water either down the drain to the sewer system or out to the landscape. For each load of laundry, a resident can decide where they want the water to go, selecting the sewer option if, for example, they’re using bleach in the wash.

Water headed for the garden flows through greywater tubing into underground mulch basins (aka swales) dug near trees or large plants. At Sercan’s home, this includes a thriving array of mulberry, plum, Asian pear, apricot, cherry, and citrus. The mulch basins serve as filters that trap particles of lint or soap as the greywater soaks down around the roots of the plants.

“On the residential level, you have control over what goes down the drain, and that impacts the quality of the water,” says Allen. Products to avoid sending into the garden include powdered laundry detergent and detergents containing salt, boron, or chlorine bleach. Because greywater contains organic matter, it should be used promptly, not stored or allowed to run out to storm drains, which lead to streams and creeks headed to the San Francisco Bay.


Left: Anna from Mariposa Gardening & Design assembles the Living Fountain at Ayse Sercan’s home. Once it’s cleaned by the plants, the greywater is routed into the blue tank and then pumped into the garden. Right:The Living Fountain newly planted with rushes, ginger, equisetum, irises, and a papyrus. The plants’ roots and soil will work to clean the greywater and make it usable for plants in the garden. (Photos courtesy of Mariposa Gardening & Design)


This Mariposa Gardening & Design living fountain cleans greywater by circulating it through plant roots and soil. (Photo courtesy of Mariposa Gardening & Design)


What About Shower and Tub?

More complex systems can capture greywater from bathtubs, showers, and bathroom sinks in addition to washing machines and guide it to multiple zones within larger gardens. In 2017, Sercan’s home was replumbed, and she’s currently having Oakland-based cooperative Mariposa Gardening & Design install one of their “living fountain” greywater systems. Unlike a simple L2L system, this design includes a circulating pump that helps the plants and soil filter the water via their naturally occurring bacteria.

“There is no better way to clean water than through plant roots and soil,” says Andrea Hurd, Mariposa’s lead designer and stonemason. “The living fountain also allows you to grow plants that increase the biodiversity in your garden. Because the system is self-contained and there’s always water filtering through it, you can also grow wetland plants. When we’re thinking about drought-tolerant gardening, we eliminate this whole body of plant life that is also good for the planet and for pollinators.” Unlike untreated greywater, the water filtered through a living fountain has enough impurities removed to run it through a drip irrigation system.

Innovations in systems for larger homes and businesses include the Hydraloop, which looks like a high-tech refrigerator. Developed in the Netherlands, it collects and cleans greywater from multiple sources and moves the disinfected water to toilets for flushing, to washing machines for laundry, and to irrigation or pools. Costs for the basic unit start at about $6,000, not including plumbing, installation, and consulting costs.

Paul Mann, CEO of the consulting and design business Water Champions, has installed Hydraloops in Marin and the East Bay. “Any system that reduces your water use and helps to keep your landscape green and fire resistant is a good investment right now,” says Mann. “As climate change and extreme drought continue to impact our supply and availability of water, we will all need to conserve to make what water we have left go farther.” At his Fairfax property, Mann was able to reduce municipal water consumption by 68 percent by using greywater from laundry, sinks, showers, and tubs, as well as rainwater collected from the roof, a $50 leak-detection device, and a $70 smart irrigation controller.

Let It Rain

“Greywater and rainwater belong together,” says Elizabeth Dougherty, whose nonprofit, Wholly H2O, gets people out into watersheds and uses citizen science, art, and education to build motivation for responsible water use. “It’s not just reusing water, but how much water you use,” says Dougherty. Shorter showers, less flushing of toilets, and mindfulness at the kitchen sink are all easy ways to cut back. “I’m thinking about my ecosystem neighbors and other living creatures every time I turn on my tap in Oakland,” she says.

A lot of rain isn’t a requirement for collecting substantial amounts of rainwater. One inch of rainfall on a 1,000-square-foot roof can yield 600 gallons, which runs from downspouts or pipes into barrels, cisterns, or other rainwater tanks. These containers should be dark to help prevent algae from growing and covered by a screen to keep leaves and bugs out. Rainwater vessels can range from small barrels to huge tanks storing thousands of gallons.

A variation is the rain garden, where sunken beds might host native and drought-tolerant plants. The beds take advantage of gravity as they capture runoff from hard surfaces like roofs, driveways, or streets. A rain garden reduces the pollutants that would otherwise run into storm drains, lakes, and streams while also adding greenery without requiring irrigation. During large storms, a rain garden helps reduce flooding and erosion.

Cost, Savings, and Rules

For people who like DIY projects, the cost of supplies for a basic L2L system is as little as $200–$400. Laura Allen recommends hiring a professional installer rather than buying a ready-made kit since each system should be customized to the particular setting. Professional installation might run $1,000–$2,000, depending on the size and setup of your home and garden.

According to the East Bay Municipal Utility District (EBMUD), an L2L system saves about 3,600 gallons a year if you have a water-efficient clothes washer and up to 11,200 gallons a year if you have an older top loader. In addition, some rebates are available: EBMUD offers $50 for the purchase of a three-way diverter valve and the Alameda County Water District offers rebates for replacing lawns with water-efficient landscapes and installing rain barrels, smart sprinkler systems, and ultra-high-efficiency toilets. The Contra Costa Water District offers $50 for installing an L2L system and rebates of $1 per square foot of lawn replaced with water-wise landscaping up to a maximum of $1,000.

California’s greywater regulations were extremely strict until 2009, when a change in the code eased the process for building simple, low-cost systems legally. If there’s no change made to the home’s plumbing and guidelines are followed, greywater systems can be installed without a construction permit.

Given the grim realities of drought and climate change, perhaps your moment to “go grey” has arrived. “This is a great time for people who haven’t yet tapped into greywater to look at it and see if it works for them,” says Allen. “Droughts can be a good opportunity to shift how we’re doing things with our homes and landscapes to be more sustainable in the long run.” ♦

Rachel Trachten writes about local food in connection to social justice, education, business, and the environment. View her stories at racheltrachten.contently.com.


Nina Gordon-Kirsch crosses Salt Springs Valley Dam, which holds back Mokelumne River tributary water on Washoe land in Calaveras County, California. (Photo by Sky Richards)


Where Does Your Water Come From?

Oakland resident Nina Gordon-Kirsch teaches an experiential class about California water resources for high school students and also works with Greywater Action as an educator and greywater installer. In July 2022, she walked more than 240 miles, tracing the origin of our East Bay drinking water from her home in Oakland to the headwaters of the Mokelumne River. Along with her team, she is now raising funds to make the journey into an educational film to show in East Bay schools as a way to help high school students learn how to “bridge the gap between tap and source.” Check out the fundraising campaign site and read this SF Chronicle story for more on the journey and documentary.



Click to Greywater Action to access a wealth of good information on greywater, water harvesting, and composting toilets plus educational courses. Their website also includes a list of local greywater installers.

Wholly H2O offers educational activities that inspire environmental stewardship by forging personal connections with local watersheds.

The websites for Alameda County Water District, Contra Costa Water District, and East Bay Municipal Utility District have information you will want to access as you contemplate and install your greywater system.

Mariposa Garden & Design offers lots of good reading on greywater concepts and how they can be carried out beautifully and effectively at your home.

Visit Water Champions to learn how you can reduce your potable water use and help pioneer a water-smart and sustainable future.

Berkeley’s Ecology Center has long maintained the EcoHouse, a demonstration home and garden located in a North Berkeley residential neighborhood. Visit the EcoHouse site for a large set of resources as well as classes, workshops, and tours of the house and garden designed to teach people from all walks of life how to make their living spaces healthier, more productive, energy and water efficient, and ecologically friendly.