El Cajon, CA Environmental Rules: Flood Elevation Requirements (2026)

060(A)(3) sets El Cajon's flood-elevation construction standards. In an AO zone, residential construction must have its lowest floor elevated above the highest adjacent grade to a height at or exceeding the depth number shown on the FIRM, plus at least one foot, or at least three feet above grade if no depth number is specified. ' In all other flood zones, the lowest floor must sit at least one foot above base flood elevation. Once built, a registered professional engineer or surveyor must certify the lowest-floor elevation, and the community building inspector must verify the structure was properly elevated before that certification goes to the floodplain administrator.

Nonresidential buildings can meet the same elevation standard or instead be floodproofed watertight below it, with a licensed engineer or architect certifying the floodproofing design. 060(D), and homes in existing manufactured home parks may instead use reinforced piers at least 36 inches above grade. Enclosed areas below the lowest floor used only for parking, access, or storage must have flood vents totaling at least one square inch of net opening per square foot of enclosed area, with openings no higher than one foot above grade.