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

Oxnard Code of Ordinances Chapter 18 governs every area of special flood hazard shown on the city's Flood Insurance Rate Maps, first adopted from the March 1, 1979 Flood Insurance Study for the City of Oxnard and updated with each FEMA revision since. Section 18-35(C)(1) sets the elevation standard: in Zone A, the lowest floor of a new or substantially improved residential structure must be elevated at least two feet above the base flood elevation, with that elevation determined under the methods in Section 18-21(B); in all other special flood hazard zones the same two-foot freeboard above base flood elevation applies, and the finished elevation must be certified by a registered professional engineer or surveyor and verified by a city building inspector before the certification is filed with the floodplain administrator.

Zone AO parcels instead key off the FIRM-listed depth number, or two feet above the highest adjacent grade if none is listed. Nonresidential buildings may flood-proof instead of elevate under Section 18-35(C)(2), but the flood-proofed structure must be watertight, resist hydrostatic and hydrodynamic loads, and be certified by a registered engineer or architect. Enclosed areas below the lowest floor used only for parking, access or storage must have flood vents totaling at least one square inch of opening per square foot of enclosed area, with openings no higher than one foot above grade.

The city engineer serves as floodplain administrator under Section 18-20, reviewing every development permit application for compliance, confirming other state and federal permits are obtained, and determining the site is reasonably safe from flooding before a permit issues under Section 18-25.