Graywater Information

What is graywater?

Graywater is water from washing machines, showers, bath tubs, and bathroom sinks.  It is water that contains some soap but is clean enough to water plants. Water from toilets, wash water from diapers, and kitchen sink water is not considered graywater in California and should not be used to water plants. For more information, reference the California Health and Safety Code Section 17922.12

Why use graywater?

Graywater can help reduce the use of high-quality drinking water for irrigation and decrease flows to our wastewater system. In concert with indoor water conservation and water-wise landscaping, using graywater can help reduce a household’s overall water use and protects the urban watershed.

Is it legal?

Yes, in August 2009, California’s graywater regulations changed, allowing for lower-cost graywater systems to be installed legally.

Do I need a permit?

A permit is not required for a one- or two-unit residential building with a graywater system that uses clothes washer discharge water only for landscape irrigation. Other graywater systems require a permit from the Department of Building Inspection (DBI) in your city or county.

Type of System Chapter 16 Permit Requirements
Clothes Washer System No construction permit required if conditions in California Health and Safety Code Section 1603A.1.1 are met.
Simple System< 250 gallons/day Permit and plans required unless exempted by Enforcing Agency. No storage.
Complex System> 250 gallons/day Permit and plans required unless exempted by Enforcing Agency. No storage.
Treated Graywater Permit and plans required unless exempted by Enforcing Agency.

 

How can I use it?

You can pipe graywater from your home directly outside and use it to irrigate plants or trees in your yard.  Graywater may be released above the ground surface provided at least two (2) inches (51 mm) of mulch, rock, or soil, or a solid shield covers the release point.

Is it safe to use graywater?

Yes, if you follow requirements while constructing your graywater system, such as minimizing contact with graywater and allowing graywater to percolate through topsoil.  Runoff, ponding or pooling of graywater and graywater contact with people or pets are prohibited.

Can I store graywater?

No, graywater may not be stored it must discharge into a mulch basin.

Resources: