San Jose, CA Landscaping Rules: Rainwater Harvesting (2026)

Rainwater harvesting is encouraged in Santa Clara County as a water conservation strategy. The California Rainwater Capture Act of 2012 (AB 1750) allows residential, commercial, and governmental rooftop rainwater harvesting without requiring a water rights permit from the State Water Resources Control Board. Small-scale systems such as rain barrels under 100 gallons and above-ground cisterns typically do not require a building permit when placed on compacted gravel or concrete pads, though setbacks from property lines and structures must be observed. Tanks larger than 5,000 gallons, tanks mounted on structures, or systems plumbed into a home require building and plumbing permits. When used for indoor potable purposes, harvested water must be treated and kept in a separate plumbing system with cross-connection controls; outdoor irrigation use is more common and simpler. Valley Water offers rebates for rain barrels and graywater-ready irrigation systems. Mosquito abatement rules require covered tanks with fine screen mesh to prevent breeding.