La Habra, CA Environmental Rules: Flood Elevation Requirements (2026)

Chapter 15.64 of the La Habra Municipal Code, adopted by Ordinance 1641 in 2004, ties every structure's lowest floor to the base flood elevation, the height reached by a flood with a one percent annual chance of occurring, also called the 100-year flood. Section 15.64.240(A) requires new or substantially improved residential construction to have its lowest floor, including any basement, elevated to or above the base flood elevation in Zone A and in all other zones; in a Zone AO the lowest floor must instead clear the highest adjacent grade by the depth number printed on the Flood Insurance Rate Map, or by at least two feet if no depth number is given.

Where the FIRM does not supply a base flood elevation, Section 15.64.160 directs the floodplain administrator to use available federal or state data or, lacking that, to derive an elevation with FEMA's Quick-2 program or the Army Corps of Engineers' HEC-HMS and HEC-RAS models. Once the structure is finished, Section 15.64.240(A)(3) requires the lowest-floor elevation to be certified by a registered professional engineer or surveyor and verified by the community building inspector before that certification is filed with the floodplain administrator. Nonresidential buildings have an alternative under Section 15.64.240(B): instead of elevating to the base flood elevation, the structure may be flood proofed watertight below that elevation, with a registered engineer or architect certifying the flood proofing design.

Manufactured homes placed in a Special Flood Hazard Area must meet the same base-flood-elevation standard under Section 15.64.270, with the chassis raised on reinforced piers when existing park lots are involved.