San Bernardino, CA Environmental Rules: Flood Zones (2026)

San Bernardino participates in the National Flood Insurance Program (NFIP) and enforces floodplain management rules consistent with 44 CFR 60.3 and the California Department of Water Resources Central Valley Flood Protection Board regulations. FEMA Flood Insurance Rate Maps (FIRMs) delineate Special Flood Hazard Areas (SFHA) within the city, including Zone A (1% annual chance flood without base flood elevations determined), Zone AE (with BFEs), Zone AO (shallow flooding from sheet flow, typical in alluvial fan areas), and Zone X (moderate and minimal risk). Major flood-prone areas include the Santa Ana River corridor, Warm Creek, Cajon Wash, and City Creek, plus alluvial fan areas below the San Bernardino Mountains where debris flow and mudflow are serious hazards. New construction and substantial improvements (work equal to or exceeding 50 percent of structure value) within SFHAs must elevate the lowest floor to or above BFE plus 1 foot of freeboard, use flood-resistant materials below the BFE, and install flood vents in enclosed areas. A floodplain development permit is required from Community Development before grading, filling, or building in SFHA zones. Substantial damage from flooding, fire, or any cause triggering substantial improvement rules must be repaired to current floodplain standards. Federally backed mortgages in SFHAs require flood insurance. San Bernardino County Flood Control District manages regional drainage including the Seven Oaks Dam and multiple debris basins in the foothills.