Graywater Systems

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Did you know that instead of sending your property’s water down the drain, you can reuse some of it to irrigate your yard instead? Some Californians are taking advantage of this simple idea and are installing graywater systems to keep their gardens green. During water shortages or droughts, graywater systems can be a reliable water supply for your plants. 

What is Graywater?

Graywater is water from indoor sources that is captured and reused on-site for irrigation. Sources of household graywater include laundry machines, bathroom faucets, showers, and bathtubs. 

Per California Health and Safety Code, Section 17922.12 and the California Uniform Plumbing Code, graywater systems cannot include any water from toilets, kitchen sinks, or dishwashers. This type of wastewater contains high organic material and possible food borne pathogens that require treatment.  

Graywater is not the same as recycled water. Recycled water is wastewater (which includes water from toilets and kitchen drains) that has been cleaned at a treatment plant and is piped to customers for non-drinking uses like irrigation. Graywater does not undergo any treatment.

Types of Graywater Systems

Laundry-to-Landscape (L2) Graywater Systems
Simple & Complex Graywater Systems

Design & Permitting Requirements

Your system must meet the guidelines in California Plumbing Code and Dublin Municipal Code (DMC) 8.88.160 if the property is within the City of Dublin to be code compliant. If you have any questions about DSRSD permitting requirements for graywater systems, email olsons@dsrsd.com.

Graywater System Design Requirements
Graywater Use Regulations
L2L System Permit Requirements

Things to Know Before Installing a Graywater System

Assess your Property: To install an L2L graywater system, the landscape must be the same elevation or downhill from the clothes washer. It is also recommended that the clothes washer is located near an exterior wall or crawlspace.
 
Choose the Right Plants to Irrigate: Graywater works well for irrigating trees, shrubs, and larger perennials and annuals. Do not use graywater to water lawns, root vegetables, or in raised beds.

Upgrade your Laundry Machine First: If you do not have an Energy Star-rated laundry machine, consider replacing it before installing a graywater system. This will ensure your property saves as much water as possible. DSRSD offers rebates to help residents purchase water-efficient models.

Additional Resources

  • City of Dublin Laundry-to-Landscape Systems Handout
  • Laundry to Landscape Graywater System Example Handout
  • Greywater Action