Sonoma, CA Landscaping Rules: Rainwater Harvesting (2026)

California Water Code § 10574 (Rainwater Capture Act of 2012, AB 1750) provides that rooftop rainwater capture does not require a State Water Resources Control Board appropriative water right. The City of Sonoma defers to the California Plumbing Code (CPC) and California Building Code for tank installation. For non-potable uses (landscape irrigation, toilet flushing), no permit is required when ALL of the following apply: (1) cistern capacity is less than 5,000 gallons; (2) height-to-width ratio is less than 2:1; (3) captured rainwater is used only for non-spray irrigation; (4) the system is installed on a structurally adequate foundation or platform; (5) no power or makeup-water connection is required. Potable rainwater systems (drinking/cooking) require a building permit and must comply with California Plumbing Code Appendix K, which Sonoma County formally adopted in January 2017; the City of Sonoma applies the same CPC framework. The City does not separately restrict rain barrels, and Sonoma Water and the Sonoma Resource Conservation District actively encourage rainwater capture for landscape irrigation.