Stanislaus County, CA Landscaping Rules: Rainwater Harvesting (2026)

There is no Stanislaus County ordinance that prohibits or specially permits residential rainwater harvesting in the unincorporated area; the County's irrigation standards even allow reclaimed water as an alternate irrigation source through an approved dual system. Because the County is silent, California state law controls. Under the Rainwater Capture Act of 2012 (AB 1750, codified at Water Code Section 10574 et seq., Part 2.4), residential, commercial and governmental landowners may install and operate rooftop rainwater capture systems, and rooftop rainwater collection does not require a water-right permit from the State Water Board. The State Water Board guidance treats simple rain barrels and cisterns used for outdoor, non-potable purposes as not needing a permit when kept under 360 gallons. Larger or more complex storage tanks, and any system plumbed into the building's potable supply, are regulated by the California Plumbing Code: a connection to a potable source requires an approved backflow-prevention device and prior notice to the local public water system operator. Above-ground tanks and any structural supports may also need a County building permit if they exceed code size or height thresholds, and setbacks in the Zoning Ordinance apply to large tanks like other structures. For most homeowners installing rain barrels for garden irrigation, no County or state permit is required. Always confirm tank size, potable-system connections, and structural support with the County Building Division before installing a large cistern.