Anaheim, CA Environmental Rules: Flood Elevation Requirements (2026)

Anaheim Municipal Code Chapter 17.28 implements the National Flood Insurance Program locally. Section 17.28.130.031 requires that new construction and substantial improvement of any structure have the lowest floor, including basement, elevated at least one foot above the base flood elevation (BFE), the one-foot freeboard above FEMA's mapped 100-year flood level. Nonresidential structures may instead meet the floodproofing alternative in 17.28.130.033: making the structure watertight below the base flood level with walls substantially impermeable to water and structural components capable of resisting hydrostatic and hydrodynamic loads, certified by a registered engineer or architect.

In Zone AO, Section 17.28.130.032 instead requires the lowest floor to sit above the highest adjacent grade by the FIRM depth number plus one foot, or at least three feet if no depth number is shown. Before a certificate of occupancy or final zoning inspection, Section 17.28.130.031 requires a registered professional engineer or surveyor to complete an elevation certificate documenting the as-built lowest floor elevation and submit it to the Planning Director. Enclosed areas below the lowest floor used only for parking, building access, or storage must have at least two flood vent openings totaling one square inch of net area per square foot of enclosed space, with the bottom of each opening no higher than one foot above grade, per Section 17.28.130.035.

A development permit under Section 17.28.100 is required before any construction begins in a special flood hazard area, and the applicant's engineer or architect must submit the proposed lowest floor elevation relative to mean sea level as part of that application. The Planning Director administers the chapter and coordinates required data submissions to FEMA under Section 17.28.120, while the City Engineer reviews whether a project would raise the base flood water surface elevation by more than one foot under Section 17.28.125.