San Diego County, CA Landscaping Rules: Rainwater Harvesting (2026)

Rainwater capture is legal and encouraged for residents of unincorporated San Diego County, and there is no county ordinance prohibiting it. The controlling law is California's Rainwater Capture Act of 2012 (AB 1750), which authorizes residential, commercial, and governmental landowners to install and operate rain barrels and rainwater-capture systems. It clarifies that collecting rainwater from rooftops for outdoor, non-potable use does not require a water-right permit from the State Water Resources Control Board. Small systems are largely exempt from permitting: rain barrels and cisterns capturing rooftop runoff for landscape irrigation are generally unregulated where capacity is below 360 gallons. Larger cisterns, elevated tanks, systems plumbed into a building, or systems intended for any indoor or potable use can trigger California Plumbing Code and county building-permit requirements, so check with County Planning & Development Services for tanks above that threshold or for structural mounting. Captured rainwater pairs well with the county's water-efficiency goals and can help meet the landscape water budget under the Water Conservation in Landscaping Ordinance. Always keep barrels covered and screened to prevent mosquito breeding, which the County Vector Control program addresses separately.