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

Lassen County does not prohibit residential rainwater harvesting, and in a dry, drought-prone high-desert county, capturing roof runoff is a practical way to supplement irrigation. The governing rules are statewide. The Rainwater Capture Act of 2012 (AB 1750), codified in the California Water Code, provides that the use of rainwater collected from rooftops does not require a water-right permit from the State Water Resources Control Board, and authorizes residential, commercial, and governmental landowners to install, maintain, and operate rain-barrel and rainwater-capture systems. A basic gravity-fed rain-barrel system that uses no electricity or pump and is not connected to a potable supply typically needs no building or plumbing permit for outdoor home use; California guidance generally treats simple exterior systems (commonly cisterns up to roughly 5,000 gallons installed on grade for outdoor non-spray irrigation without electrical power) as not requiring a permit. Larger, pumped, pressurized, or indoor-plumbed systems will generally require permits, inspection, or licensed installation through Lassen County's Building Department and may need to meet California Plumbing Code provisions; a Landscape Contractor (C-27) may install the exterior components not attached to a structure. Harvested rainwater is also outside the State Water Board's potable-water timing rules, so it can be used for irrigation any time, including right after rain.