Daly City, CA Environmental Rules: Stormwater Management (2026)

Stormwater discharges in Daly City are regulated by the Bay Area Municipal Regional Permit (MRP) issued by the San Francisco Bay Regional Water Quality Control Board (Order R2-2015-0049, amended 2019). Daly City participates through SMCWPPP, the San Mateo Countywide Water Pollution Prevention Program established in 1990 and operated as 'Flows To Bay' across 20 San Mateo County cities. Provision C.3 of the MRP requires post-construction stormwater treatment for Regulated Projects that create or replace 10,000 sq ft or more of impervious surface (2,500 sq ft for special land uses including auto service, retail gas, restaurants, and uncovered parking). Treatment must use Low Impact Development (LID) measures such as bioretention, pervious pavement, or rainwater harvesting sized per the C.3 Stormwater Technical Guidance. Construction sites disturbing 1 acre or more must also obtain coverage under the statewide Construction General Permit (Order 2009-0009-DWQ, as amended) and prepare a SWPPP. Daly City's Title 15 Environmental Protection chapters and Title 12 building/engineering provisions implement these requirements at the local level.