Riverside, CA Landscaping Rules: Rainwater Harvesting (2026)

Riverside follows California's uniform framework that allows property owners to capture rainwater from rooftops without a permit for non-potable outdoor use such as landscape irrigation, provided the system meets basic health and safety standards. The California Rainwater Capture Act of 2012 exempts residential systems under 5,000 gallons from a plumbing permit when the water is used only for outdoor, non-potable purposes and is not cross-connected with the domestic water supply. Barrels must have a sealed, screened inlet (mesh of 1/16 inch or finer) to prevent mosquito breeding — a concern for West Nile virus in the Santa Ana River watershed. Overflow must discharge away from structures and not onto neighboring property. Rainwater used indoors (toilet flushing, laundry) requires a plumbing permit, backflow prevention, and purple-pipe labeling to conform to the California Plumbing Code. CALGreen Tier 1 encourages rainwater and graywater reuse and provides optional credits for new construction. RPU has historically offered limited rebates on rain barrels in partnership with regional agencies, and the State Water Resources Control Board publishes a residential graywater and rainwater guide. Homeowners in hillside or slope-stability zones should avoid large-tank placement on steep grades without geotechnical review, and HOAs in Riverside may not prohibit rain barrels categorically under state policy favoring water conservation.