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

Single-family homes outside a Development Permit or Chapter 15.11 water-efficiency review must disconnect roof rain leaders and downspouts from the storm drain and route them to splash blocks draining onto landscaped areas. If the Building Official finds that technically infeasible, the code lets the owner substitute an equivalent stormwater alternative consistent with the regional NPDES permit: including directing roof runoff into a rainwater harvesting system (rain barrels or cisterns) for on-site non-potable use, routing hardscape runoff to landscaped areas, or building permeable driveways and walkways. There's no separate permit or registration just to install rain barrels; it only comes up as a compliance path under the blight-prevention drainage rule, and the infeasibility call is the Building Official's.