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

Section 7-142.1C1 sets the elevation standard for residential construction in every area of special flood hazard. In zones AE, AH and A1-30, the lowest floor, including any basement, must sit at or above the base flood elevation (BFE) shown on the FIRM. In an AO zone, the lowest floor must clear the highest adjacent grade by the depth number printed on the FIRM, or by at least two feet if no depth number is given. In an unnumbered A zone with no BFE on the map, the standard reached under Section 7-141.2C applies instead, and Section 7-142.1C1d sets a fallback of two feet above the highest adjacent grade, eighteen inches above the highest curb elevation across the lot, or, for a defined older neighborhood bounded by Westfield Avenue, Henderson Avenue, Prospect Street and Newcomb Street, one foot above the highest adjacent grade for construction completed before the article's adoption.

Once the structure is finished, Section 7-142.1C1 requires the lowest floor elevation to be certified by a registered civil engineer or licensed land surveyor and verified by the City's building inspector before the Floodplain Administrator will sign off. Nonresidential buildings can meet the same elevation standard or, under Section 7-142.1C2, be dry-floodproofed and certified watertight by a registered engineer or architect instead. The article does not layer an additional freeboard margin on top of the mapped BFE outside the AO- and A-zone fallback figures; elevation to the BFE itself, plus certification, is the operative floor.