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Plan the graywater route

Laundry-to-landscape systems have limitations that affect the graywater’s path of travel through a landscape, including topography (slope), number of distribution points (i.e., mulch basins), and piping placement.

If you need to get past a cement patio, walkway or another impervious surface, consider installing a permeable hardscape (State of California Water Board). Or, go under or cut a strip from the hardscape. Review the distance rules provided in the Graywater Rebate Requirements for additional details.

From your clothes washer, the graywater piping will be in a shallow trench (deep enough to avoid trip hazards) connecting each mulch basin. A single mulch basin may have more than one mulch shield (graywater outlet) and the mulch basin can be any shape (circles or trenches are most common). The bottom of the mulch basin should be as flat as possible.

For every one foot run of pipe you lay down, you may go down ¼ inch in grade. So, for a 20-foot run, the line will eventually be 5 inches below the grade from where you started in a completely flat yard. The graywater piping may tee-off to ½-inch lines in most mulch basins as long as there’s a continuous route between the clothes washer and the last mulch basin where the piping stays the same diameter as the clothes washer’s washer line throughout.