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

Collecting rainwater is legal in Santa Clara County and across California. Under the state's Rainwater Capture Act of 2012 (AB 1750), using rainwater collected from rooftops does not require a water-right permit from the State Water Resources Control Board, and residential, commercial, and governmental landowners may install and operate rain-barrel and rainwater-capture systems. For typical home use, installing a rain barrel or cistern that captures roof runoff generally does not require a local building or plumbing permit; however, if installation requires disconnecting a downspout from the sewer, the local agency may require a permit to properly cap that sewer connection. Harvested rainwater is intended for outdoor, non-potable uses such as landscape irrigation and gardening on the property where it is collected. Santa Clara County's own Sustainable Landscape Ordinance encourages efficient design and the use of alternative water sources, consistent with the state Model Water Efficient Landscape Ordinance, which incentivizes graywater, harvested rainwater, and recycled water. Larger or plumbed rainwater systems, potable use, or systems that supply fixtures may trigger California Plumbing Code requirements and permits. For a basic gravity-fed barrel used for garden irrigation, there is no County prohibition and the activity is supported by both state law and the County's landscape goals. Residents planning a larger cistern, pumped system, or any indoor connection should confirm permit requirements with County Building.