by Renee Roth, Save Our Water, Ojai!
Greywater (also spelled grey water and graywater) is household waste water that is re-used and recycled out to the landscape as a source of irrigation for plants. Household sources of greywater include: laundry, showers, bathtubs, and bathroom sinks. Greywater is also a unique source of residential waste water that is a great way to reduce your potable water use. Simple systems like a laundry-to-landscape (L2L) do not require a permit.
The image above shows a simple greywater laundry-to-landscape set up, from Page 81 of The Water-Wise Home – How to Conserve, Capture and Reuse Water in Your Home and Landscape book by Laura Allen of Greywater Action.
When Is a Permit NOT Required?
The California plumbing code (Chapter 15 of the CA Plumbing Code, available here) has been revised so a permit is NOT required for a greywater clothes washer system (aka Laundry-to-Landscape) where the water is directed out to the landscape into mulched basins. The “greywater clothes washer system” is defined as a system utilizing only a single domestic clothes washing machine in a one- or two- family dwelling that meets the following:
- The method for distribution cannot use a secondary pump and must rely on gravity.
- The amount of water from the washing machine is considered to be 15 gallons per person per day, e.g. 60 gallons per day for a 4 person household, but it gets complicated based on type of washing machine, soil type, size of drainage area etc. Consult with a trained landscaper familiar with installing greywater systems.
- Laundry soaps used must be biodegradable and non-toxic. They should also be low in salt (sodium) and boron (Borax) two common ingredients that are non-toxic to people, but harmful to plants and soil. Hydrogen peroxide bleaches should be used instead of chlorine bleaches.
Ventura County Regulations
Call the Ventura County Building Division at (805) 654-2771 during the design phase to prevent any plumbing or siting issues. Reuse of greywater from kitchen sinks is currently prohibited. Ventura County persons to contact via email:
Matt Wyatt, Ventura County District Manager, Matt.Wyatt@ventura.org, 805-654-2791
David Hansen, West County (Simi Valley) District Manager, email@example.com, 805-582-8064
In Ventura County, permits are required for greywater construction that alter plumbing pipes. For example, you will need a permit for a greywater system for outdoor irrigation if the system meets any of these conditions:
- Collects water from showers, sinks, or baths
- Alters the plumbing (i.e., whenever you cut into the drainage plumbing to access the greywater).
See the GW-2 permit requirements for sink and shower installation guidelines here.
Ventura County Water Use and Efficiency webpage is here
which includes information on rain tank catchment systems P-14.
Santa Barbara and Santa Barbara County Greywater Guidelines
Both the City of Santa Barbara and the County of Santa Barbara have good guidelines for unpermitted greywater systems. They are both more permissive, and have good manuals and links to reusing both rainwater and greywater. See their resources below.
NEW Santa Barbara County Greywater Handbook in English and Spanish is available on their Website
- Greywater Action: Cofounded by Laura Allen, a non-profit dedicated to educating residents about greywater, its uses, and how people can use it to conserve water. Training classes are provided and upcoming Greywater Action events can be found here
- Graywater—A potential source of water: Article by Yorem Cohen from the UCLA Institute for the Environment (2009)
- California Greywater Guide to the California Greywater Code of 2010
- San Francisco Public Utilities Commission Greywater Design Manual for Outdoor Irrigation (2012)
- Conserving water with graywater system worth the effort, Ventura County Star article, November 2016
Visionaries /Leaders of GREYWATER and RAINWATER HARVESTING
Laura Allen’s Website Greywater Action http://greywateraction.org
Book:The Water-Wise Home by Laura Allen Storey Publishing 2015.
Greywater Green Landscape How to Install Simple Water-Saving Irrigation Systems in Your Yard by Laura Allen, Storey Publishing, 2017
Website of Art Ludwig, who started the greywater regulation revolution in Santa Barbara (1989) http://Oasisdesign.net AND Book: The New Create an Oasis with Greywater: Choosing Building and Using Greywater Systems. Art Ludwig, Oasis Design, 2006.
Brad Lancaster’s website www.harvestingrainwater.com AND Book: Rainwater Harvesting for Drylands and Beyond, Second Edition, Volume 1. Brad Lancaster, Rainsource Press, 20013.
San Francisco Graywater Design Manual for Outdoor Irrigation. http://sfwater.org/index.aspx?page=100
San Luis Obispo Guide to the use of Graywater http://www.mbnep.org/wp-content/uploads/2014/12/Graywater_08_20_09.pdf
Online Parts Info
Water Wise Supply has barbed fitting kits you can order at https://www.waterwisesupply.com/
City of Pasadena Greywater Video
Ask This Old House episode on greywater: https://www.thisoldhouse.com/how-to/how-to-install-graywater-irrigation-system
MOVIES TO LOOK FOR: Watershed Revolution, DAMNATION and WATERSHED: Exploring a New Water Ethic for a New West
SOAPS and Detergents
Hand soaps and shampoos by and large do not damage plants or clog soil profiles, in fact greywater is a light fertilizer. Laundry detergents commonly have sodium and boron which are chemicals that can have a negative effect on landscapes. The following are detergents or cleaners to avoid:
- Bleaches or softeners
- Detergents that advertise whitening, softening, and enzymatic powers
- Detergents with the following ingredients: boron, borax, chlorine, bleach, petroleum distillers, sodium and peroxygen
- Products designed to open clogs without scrubbing
- Water softeners that use sodium chloride
Common laundry soaps that do work (they are salt and boron free, and pH neutral) include Oasis, Ecos, Biopac liquid detergent, and Vaska. There are also soap alternatives that are greywater friendly, like soap nuts, and “wonder balls”.
Irrigation Set UP
Trees and common edible plants can be used in a greywater system as long as no edible parts touch the actual greywater flow. The foods produced above ground from plants rooted in greywater are just as fit to eat as plants grown in drinking quality water. The water needs to flow into mulched basins to clean and soak into the root zone of the plant. A picture of a mulched basin is included below.