Los Angeles County, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard required
- 1 foot above base flood elevation
- Applies to
- Santa Monica Mountains Coastal Zone
- Flood zones covered
- FEMA Zones A, AE, AH
- Citation
- LA County Code Section 22.44.2102(I)(4)
- Enforced by
- County Building Official, Public Works
Summary
In the unincorporated Santa Monica Mountains Coastal Zone, new residential construction in FEMA A, AE, or AH flood zones must have its lowest floor built at least one foot above the base flood elevation.
For residential structures in Zones A, AE, or AH on a FIRM, the lowest floor (including basement) shall be elevated at least one (1) foot above the base flood elevation, where base flood shall mean a flood having a one percent chance of being equaled or exceeded in every year (a 100-year flood).
Full Breakdown
Los Angeles County's Santa Monica Mountains Local Implementation Program sets the county's own flood-freeboard standard for the unincorporated Coastal Zone. Under LA County Code Section 22.44.2102, new development in a mapped special flood hazard area must be sited outside it if feasible; if not, residential structures in FEMA Zones A, AE, or AH must have their lowest floor, including any basement, elevated at least one foot above the base flood elevation, defined as the 100-year flood. Manufactured homes get the same one-foot buffer on an anchored permanent foundation, while non-residential buildings need only reach base flood elevation. The County Engineer and Building Official confirm compliance through the coastal development permit and building-permit process.
Violations & Fines
Building without the required freeboard blocks permit sign-off: the Building Official withholds the certificate of occupancy until a registered engineer certifies lowest-floor elevation, and non-compliant structures can void National Flood Insurance Program coverage.
Frequently Asked Questions
Does this freeboard rule apply to the City of Los Angeles?
What about lots outside the Coastal Zone?
Sources & Official References
Other rules in Los Angeles County
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