Harvesting graywater in Sonoma County saves water
A graywater system will allow you to reuse laundry water to irrigate ornamentals and many trees, efficiently saving water in the North Bay’s summer dry and drought-prone climate.
BY JEFF COX
March 6, 2025 | PRESS DEMOCRAT
Clare Pitton and Sam Cramer with their son, who’s name they prefer not to give, kneel next to an access cover to their home Laundry-
to-Landscape graywater system that provides water for a series of young fruit trees. (Beth Schlanker / The Press Democrat)
While our lovely Mediterranean climate pours on the sunshine and fine weather for most of the growing season, it does have one major drawback: rain is less than scarce from May to October.
This means that unless we create a full-blown irrigation system and pump it regularly with fresh water, some spectacular perennials that need regular summer water and continually-moist soil won’t stand a chance in our summer drought. Among these are Eupatorium Joe Pye Weed, ‘Venusta’ Queen-of-the-Prairie, Crested Gentian, Bigroot Cranesbill ‘Ingwersen’s Variety’, Hibiscus ‘Lord Baltimore’, Lobelia Cardinal Flower, Lysimachia Gooseneck Loosestrife, Myosotis Forget-Me-Not, Trollius Globeflower ‘Golden Queen’, and Veronicastrum White Culver’s Root, among many others.
Unless we have a drilled well on our property, water is an expensive commodity. Keeping a bed of flowering perennials and annuals well-watered through the summer drought can expand water bills quickly, especially when added to the rest of the water that runs through the house from sinks, bathtubs and showers, dishwashers, kitchen sinks, toilets, spigots for hoses, water features, and laundry washing machines.
Most of these uses produce blackwater ― water contaminated with bacteria from human waste or household chemicals like antiseptic cleansers washed down drains in tubs and showers, and even soaps and detergents made with chemicals containing phosphorus, an element that causes eutrophication of groundwater in streams, ponds, and lakes. Blackwater is carried to septic systems with drain fields or to municipal sewage treatment plants if you live in town.
There is one source of household water outflow that is relatively safe for you, your plants and the environment. It’s not pure ― you wouldn’t want to drink it ― but it’s not dangerous like blackwater either. It’s called graywater (or greywater in many references), and it comes from your washing machine.
Depending on the kind of machine you use for laundry ― front loader, top loader, or a modern “high efficiency” top loader ― an average load can use between 15 and 30 gallons of water, or even 40 gallons if you have a venerable top loader with an agitator that swishes the clothes back and forth in a tub of water.
Where does that water go after the wash is finished? Down the blackwater pipe to oblivion unless you have a system that uses the graywater on your property.
For your food garden to be completely safe, a graywater system should be used to water flower beds or mixed plantings of annuals, perennials, ornamental shrubs. Most trees and even fruit trees that need regular summer water can accept graywater as long as the water doesn’t come in contact with the edible fruit.
If you do a couple of loads of laundry a week and use 20 gallons per load, that’s 40 gallons of water each week that will support thirsty ornamentals throughout our dry summers without adding a penny to your water bill.
Laundry-to-landscape systems with graywater from a washing machine are the only graywater systems that don’t require a septic permit from Permit Sonoma, the county’s agency that approves irrigation plans. That doesn’t mean there aren’t rules for graywater systems ― mainly setback requirements. For example, your graywater outflow must be at least 100 feet from water supply wells and streams or lakes, two feet from buildings, and one and a half feet from property lines adjoining your neighbor’s property, among other examples listed at the Permit Sonoma website, pdne.ws/4bunu9O.
See working graywater systems up close
You can find out everything you need to know about constructing a graywater system by contacting Liz Platte-Bermeo, climate resilience program manager at Daily Acts in Petaluma ([email protected]). Over the past 23 years, this environmental education nonprofit has taught 78,710 people in our area about ways to save water and mitigate the impact of climate change.
“We’ve installed water-wise landscape projects at 29 schools, parks, and residences so far,” Platte-Bermeo said. “This includes 17 graywater and rainwater reuse systems, saving 1.6 million gallons of water every year.
“By 2026, we will have completed 125 site designs and 60 installations, created 1.5 acres of natural habitat and saved millions of gallons of water through our Land Resilience Partnership Program. We’re accepting applications to join the program until April 30 of this year,” she said.
Daily Acts will present a free Laundry-to-Landscape graywater tour March 15 in Petaluma. Participants will explore the gardens of three properties in midtown that showcase graywater systems in action, hear what the property owners have to say about their systems and learn about system design and installation. For more information, go to pdne.ws/41IVBaF.
A PVC pipe leads from the laundry room to the yard as part of the graywater system. (Beth Schlanker / PD)
One of the systems is at the home of Clare Pitton and Sam Cramer, whose system was installed by Daily Acts and The North Bay Conservation Corps last summer. They even planted a number of fruit trees that will be watered from the system.
“When we bought our house a couple of years ago the yards were totally a blank slate. We knew we wanted to plant medicinals, fruit, vegetables and herbs,” Pitton said. “When we mentioned that to Daily Acts they said we can do the laundry graywater and just route it straight to some fruit trees. Brand new fruit trees use a ton of water and we have to do a ton of laundry because we have a young child. It feels really good knowing water is going straight to the trees and helping them grow and not going straight out to the sewage.”
Daily Acts planted a new fuyu persimmon, clementine mandarin, pear, pluot, Fuji apple and elderberry. During the winter a switch enables the couple to change to sewage to avoid overwatering. Valves also enable them to control the water when the system is in graywater mode.
Daily Acts and Conservation Corps North Bay employees install a Laundry-to-Landscape graywater system at the home of
Clare Pitton and Sam Cramer in Petaluma Tuesday, Aug. 13, 2024. (Photo courtesy of Clare Pitton)
“We look out to our yard and see the life in it and the beauty of the trees. There are birds that come by,” said Pitton. “I couldn’t have been more happy with Daily Acts. They were just so easy to work with, educated and knowledgeable and they guided us through the process start to finish.”
If you want to learn about Daily Acts’ upcoming activities like graywater tours and hands-on workshops, you can visit dailyacts.org.
Use plant-friendly laundry soap
The folks at This Old House have created an entry-level tutorial on graywater systems and its do’s and don’ts that you can access at thisoldhouse.com. It’s obviously important to use a plant-friendly laundry soap if your graywater is going to the garden, but it’s also important not to use products like bleach or dry powdered detergents that tend to be alkaline and can harm acid-loving plants like blueberries, azaleas, and rhododendrons. This Old House’s tutorial will help you find safe cleansers.
Besides the ornamentals listed above, other thirsty ornamentals you can sustain with graywater include sunflowers (Helianthus annuus), cattails (Typhus spp.), water lilies (in a basin), ferns, hydrangeas (Hydrangea spp.), marigolds (Tagetes spp.), and even rosemary.
Staff Writer Meg McConahey contributed to this story. Reach her at [email protected]. Jeff Cox is a garden and food writer based in Kenwood. Reach him at [email protected].