Rancho Cucamonga, CA Environmental Rules: Stormwater Management (2026)

Stormwater management in Rancho Cucamonga is governed by the San Bernardino County MS4 Permit (NPDES Permit CAS618036) issued by the Santa Ana Regional Water Quality Control Board, which is incorporated into Municipal Code Chapter 19.08. The ordinance prohibits any non-stormwater discharge into the municipal storm drain system, including wash water from vehicle washing on public streets, pool backwash, irrigation runoff, concrete rinseate, and hazardous waste. Construction projects disturbing one acre or more must obtain coverage under the State Construction General Permit, prepare a Stormwater Pollution Prevention Plan (SWPPP), and submit a Notice of Intent through the SMARTS system to receive a Waste Discharger Identification (WDID) number. Smaller projects still require Best Management Practices (BMPs) including silt fencing, gravel bag check dams, stabilized construction entrances, and covered material storage. Post-construction, new developments must implement Low Impact Development (LID) features such as bioretention basins, permeable pavement, and infiltration wells. Illicit discharge complaints are handled by Engineering Services.