- All greywater must be gravity-fed and distributed from the clothes washer to a pre-approved landscape area that is large enough to absorb the greywater.
- 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.
- The landscape area with mulch basins must be sufficiently sized to prevent runoff and pooling of greywater.
- The greywater system may have one or more valve zones. Mulch basins within each zone must meet or exceed the required square footage provided.
- Mulch must be replenished every 3-5 years or when mulch in the basins has decomposed.
Greywater must:
- Not be stored, not runoff into streets and waterways, and not pond or pool on the surface.
- Not be used to irrigate crops or come in contact with the 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 greywater 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.