Fairfield, CA Environmental Rules: Flood Zones (2026)

Fairfield Municipal Code Chapter 8A (Flood Damage Prevention) adopts by reference the Federal Insurance Administration Flood Insurance Study and accompanying Flood Insurance Rate Maps (FIRMs) and Floodway Maps for the City of Fairfield. The ordinance restricts new construction and substantial improvements in Special Flood Hazard Areas (SFHAs, generally Zone A and Zone AE on FEMA maps) to ensure structures resist flood damage. The city has regulated SFHA development since 1971, joined the National Flood Insurance Program (NFIP) in 1984, and aligns its building standards with FEMA requirements and the California Building Code Appendix G. Flood-prone reaches include portions of Suisun Creek, Green Valley Creek, Dan Wilson Creek, Ledgewood Creek, and Union Creek; the 100-year floodplain (1% annual chance) is the regulatory boundary. Within the floodway, no fill or new construction is allowed unless an engineered no-rise certification demonstrates no change in flood elevations. Within the broader SFHA, residential structures must have the lowest floor elevated to or above the Base Flood Elevation; non-residential structures may be elevated or flood-proofed to that elevation. Substantial improvements (work valued at 50 percent or more of the structure's market value) require the entire structure to be brought into compliance. The Public Works Department provides flood-zone determination letters for a nominal fee ($20 historically); FIRMs are also available at the Fairfield-Suisun Community Library and on FEMA's Map Service Center.