All graywater must be gravity-fed and distributed from the clothes washer to a pre-approved landscape area that is large enough to absorb the graywater.
Mulch basins are required. A mulch basin is a trench dug around the outer edge of a plant's drip line and back-filled with mulch. A plant's "drip line" is an imaginary line drawn from the outside branches of a plant down to the soil (see inset image). Additional information is in About Graywater.
The landscape area with mulch basins must be sufficiently sized to prevent runoff and pooling of graywater.
A specific required square footage will be provided before or upon receiving your Notice to Proceed. This square footage is based on the amount of graywater expected to be produced and the landscape’s soil type.
The graywater system may have one or more valved zones. Mulch basins within each zone must meet or exceed the required square footage provided.
The site where graywater is used must be in an area where seasonally high groundwater is at least five feet below ground surface. This will be verified by the District using available information.
Graywater must:
Not be stored, must not runoff into streets and waterways, and must not pond nor pool on the soil surface.
Not be used to irrigate root crops or edible parts of food crops that touch the soil.
Be contained on the site where it is generated.
Be distributed subsurface or released to an area covered by a minimum of two inches of soil, bark, rock, mulch, or appropriate permeable cover.
Have an unobstructed exit route into the landscape (for example, if every valve is accidentally closed, the graywater is still able to reach the landscaping).
Avoid shallow utilities (water, gas, electric) or septic systems by calling the Underground Service Alert at (800) 227-2600 or 811 before you dig.
