Sink Drain

Captured graywater can be used for gardening or flushing toilets

What is Graywater?

Water used for bathing and laundry may go down the drain, but it doesn't need to go to waste. You can put it to good use on your landscape — safely and legally.

Up to 40 percent of your indoor water can be captured and reused as graywater. Sources of graywater in the home include the laundry, bathroom faucets, showers, and bathtubs. Kitchen sink, diaper soiled water, and "blackwater" (toilet flush water) are not acceptable sources of graywater.

Why use Graywater?

During water shortages or drought, graywater used for landscape irrigation can be a reliable supply of water for your plants. Graywater also provides plants with added nutritional benefits. In some cases, with permitting, graywater may also be used for toilet flushing or laundry.

Using graywater:

  • reduces the use of fresh water
  • lowers water bills
  • puts less strain on treatment systems and septic tanks
  • reduces energy and chemicals used for wastewater treatment
  • recharges groundwater and reclaims nutrients

When should Graywater not be used?

Graywater is not recommended in these situations:

  • small landscape areas
  • watering vegetable gardens
  • systems where drain pipes are not accessible
  • soil is too permeable or impermeable
  • when the amount of water use doesn't justify the cost of installation


EBMUD offers a rebate of up to $50 per graywater system 3-way diverter valve. If the cost of the valve is less than $50, only the actual purchase price will be rebated. Rebates will be issued by check or in the form of a credit to an EBMUD account.


To be eligible, you must

  • Be an EBMUD customer
  • Submit a completed Graywater Financial Incentive application form (see below)
  • Provide a copy of the receipt for the 3-way diverter valve within 90 days from the date of purchase.


Eligible customers must complete and sign an application form (see below). Mail to:

EBMUD Water Conservation Division
P.O. Box 24055, MS 109
Oakland, CA 94623.
Document Type Size
Graywater Rebate Application PDF <1 MB

Contact Us

Phone 1-866-403-2683

Graywater resources

This section is provided by EBMUD as a resource for our customers. The list is not comprehensive and should not be considered as an endorsement of any of the listings. For more information about graywater or to be listed as a resource please contact EBMUD.

Berkeley EcoHouse
The Ecology Center's mission is to promote environmentally and socially responsible practices through programs that educate, demonstrate, and provide direct services.

Greywater Action - For a Sustainable Water Culture
Greywater Action is a collaborative group of educators, designers, builders, and artists who educate and empower people to build sustainable water culture and infrastructure. Includes why to use graywater, how to choose, build and use graywater reuse systems, studies, regulations, and many other resources.

Graywater Policy and Science Center
A Wiki-based site for the discussion of efficient use of time and money on the part of Government and other stakeholders in the effort write California's new graywater standard.

New Mexico State University
Study done by the university on the Safe Use of Household Graywater.

The Pacific Institute
The Pacific Institute works to create a healthier planet and sustainable communities by conducting interdisciplinary research and partnering with stakeholders to produce solutions that advance environmental protection, economic development, and social equity - in California, nationally, and internationally.

Oasis Design
Oasis Design is a private business providing information on graywater issues such as: Why use graywater, how to choose, build and use graywater reuse systems, regulations, studies, science and examples. Includes graywater irrigation, graywater treatment, graywater filters, high tech indoor graywater reuse and graywater management in developing countries.

The University of Massachusetts Amherst
Common uses and practices for residential home graywater.