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

San Ramon's flood-zone management is governed by the federal National Flood Insurance Program (NFIP), FEMA Flood Insurance Rate Maps (FIRMs) for Contra Costa County, and the San Ramon Municipal Code floodplain management chapter. Primary mapped flood hazards are along San Ramon Creek (which flows through central San Ramon near the Iron Horse Trail), Alamo Creek, and their tributaries, particularly in older neighborhoods west of I-680 and in portions of the Dougherty Valley specific plan area near drainage corridors. Properties in Zone A or AE (1% annual chance flood, the 'base flood' or '100-year flood') are Special Flood Hazard Areas (SFHAs). Federally-backed mortgages on SFHA properties require flood insurance. The city's floodplain management ordinance requires: new residential construction in SFHAs to elevate the lowest floor (including basement) at least 1 foot above Base Flood Elevation (BFE); non-residential structures to either elevate or be dry-floodproofed; substantial improvements (projects over 50% of structure value) trigger compliance for the entire structure; anchoring and flood-resistant materials required below BFE; fill and grading regulated to avoid displacing flood capacity. Elevation Certificates (FEMA Form 81-31) are required at permit submittal and post-construction. The Contra Costa County Flood Control and Water Conservation District manages regional drainage and creek improvements. San Ramon's NFIP Community Rating System (CRS) participation may provide policyholder discounts. Residents can check flood zone status via the FEMA Flood Map Service Center using their address.