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

Enacted by Ordinance No. 2000 for National Flood Insurance Program compliance, the flood plain regulations apply to all areas of special flood hazard designated on the FIRM. A development permit from the Flood Plain Administrator is required before any construction in these areas. New construction must be anchored against flotation, collapse, or lateral movement, built with flood-damage-resistant materials, and designed so electrical, heating, plumbing, and air conditioning equipment stay above flood levels. New residential construction, including manufactured homes, must have the lowest floor, including any basement, elevated to the flood depth number shown on the FIRM above the highest adjacent grade, or at least two feet above grade if no depth number is specified; in AR zones, builders use whichever is lower of the AR base flood elevation or three feet above the highest adjacent grade.

Manufactured and modular homes must be secured to an anchored foundation and either meet that same elevation or sit on reinforced piers at least 36 inches above grade. Once built, a registered professional engineer or surveyor must certify the lowest floor's elevation, and a City Building Inspector verifies it before the Flood Plain Administrator signs off. Non-residential buildings may instead be flood-proofed watertight below the required elevation if a registered engineer or architect certifies the walls and structural components can resist hydrostatic and hydrodynamic loads.

Enclosed areas below the lowest floor used only for parking, access, or storage must include flood-water equalization openings, either engineer-certified or at least two openings totaling one square inch of area per square foot of enclosed space, with opening bottoms no higher than one foot above grade.