WHAT IS GRAYWATER?
Graywater systems capture the water from clothes washing machines, bathroom sinks, showers, or bathtubs and redirect that water to outdoor irrigation.
Graywater can contain soap and detergent but is generally considered clean enough to water trees, shrubs, and lawns but cannot be used in a vegetable garden.
Graywater does not include water from kitchen sinks, toilets, utility sinks, or dishwashers.
WHAT ARE THE BENEFITS OF A GRAYWATER SYSTEM?
Graywater is an innovative way to conserve water. Using graywater increases people’s mindfulness of where water comes from and where it goes.
Graywater helps reduce potable (drinking quality) water used for outdoor irrigation and decreases the amount of water going into wastewater treatment facilities.
Graywater is safe to use for outdoor irrigation when the system is installed correctly and when proper Use and Maintenance Guidelines are followed. Depending on the individual property and the type of system, graywater can save between 16% to 40% in outdoor water use.
ARE THERE ANY CITY OR COUNTY REQUIREMENTS?
The California Plumbing Code allows graywater systems connected to bathroom sinks, showers, or bathtubs to be installed in residences.
The California Plumbing Code does not require construction permits for graywater systems that use water from a clothes washing machine (known as Laundry to Landscape) where the existing plumbing system is not being modified and pumps are not being installed.
For all other graywater systems, the California Plumbing Code requires the property owner to consult with the County Health Department to ensure that public health concerns are addressed and County permits are obtained when necessary.
Burlingame residents interested in graywater must comply with City of Burlingame and San Mateo County requirements. A backflow prevention device is required by the City of Burlingame on all graywater systems when there is the potential for cross-connection between the potable drinking supply and a graywater system.
The following are San Mateo County’s graywater system requirements:
1. A permit IS required for any graywater system that proposes to use treated graywater for surface drip or spray irrigation, or untreated graywater used for subsurface distribution beyond the scope of a simple clothes washer (Laundry to Landscape) graywater system.
2. Property owners that intend to install a non-potable water system must submit an Environmental Health Review Application with the County, along with three sets of plans showing details of the proposed system's installation.
3. Applications can be obtained from San Mateo County Environmental Health by calling 650-372-6200.
WHAT IS A LAUNDRY TO LANDSCAPE SYSTEM?
A graywater system comprised solely of a clothes washing system, commonly referred to as a as Laundry to Landscape system, which diverts graywater to sub-surface irrigation or an appropriately configured and maintained mulch pile. A property owner does not need to prepare and submit plans and is not required to obtain a permit from the County Department of Environmental Health.
Laundry to Landscape graywater systems are gaining popularity since they generally do not require permits and are simpler to install relative to other graywater systems. This type of graywater system must meet all requirements specified in Section 1602.1.1 of the Uniform Plumbing Code. The San Francisco Public Utilities Commission has a thorough graywater Design Manual which details Laundry to Landscape systems (see link below).
To ensure the safe installation and correct use of graywater systems the City of Burlingame recommends that interested residents seek the expertise of a specialized plumbing contractor to plan and install any graywater system.
GRAYWATER SYSTEM RESOURCES
- San Francisco Water graywater information and design manual
- Greywater Action, a non-profit that provides resources, trainings, and news on graywater
- San Mateo County Water Programs (Click the Materials and Links tab at bottom of page)