Montgomery, AL Environmental Rules: Flood Elevation Requirements (2026)

Article X of Chapter 5 implements the National Flood Insurance Program locally. Section 5-652(1) requires that in all special flood hazard areas designated A, AE, or AH, new construction and substantial improvement of any structure or manufactured home shall have the lowest floor, including basement, elevated no lower than two feet above the base flood elevation, also referred to as the design flood elevation. That two-foot cushion is Montgomery's freeboard, defined in Section 5-605 as a safety margin above the calculated flood level. Manufactured homes must meet the same two-foot freeboard.

If solid perimeter foundation walls are used, the walls need flood openings sized to let water pass through automatically, per Section 5-652(4). Non-residential structures may dry-floodproof instead of elevating under Section 5-652(2): the building and its utilities must be watertight to two feet above the base flood elevation, with the design certified by a professional engineer or architect licensed in Alabama. Critical facilities such as hospitals and fire stations must clear the special flood hazard area entirely, or if built inside it, elevate the lowest floor four feet above the base flood elevation.

Every property owner in a special flood hazard area needs a floodplain development permit before building, issued by the floodplain administrator under Sections 5-618 and 5-637, and the administrator tracks substantial-damage determinations over a ten-year lookback under the article's cumulative-damage rule.