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

Decatur builds one foot of freeboard into its standard. Where base flood elevation (BFE) data is available, new construction, reconstruction or repairs made to a repetitive loss structure, and substantial improvement of any structure or manufactured home must have the lowest floor, including basement, elevated no lower than one foot above the BFE, also called the design flood elevation (DFE). When solid foundation perimeter walls are used, flood openings must be provided under § 25-32(b)3: at least two openings per enclosed area, a total net area of not less than one square inch per square foot of enclosed area, in at least two walls, with the bottom of each opening no higher than one foot above grade.

Non-residential structures in AE or AH zones can be dry floodproofed instead of elevated, but must be watertight to at least one foot above the BFE and certified by an Alabama licensed engineer or architect to ASCE 24 standards. Manufactured homes must sit with the lowest floor one foot or more above the BFE. Mechanical, electrical and plumbing devices in an enclosure go not less than one foot above the BFE. Structural fill must have a top no lower than one foot above the BFE and the nearest wall must be set back 25 feet from the floodplain boundary. Storage of hazardous substances in residential structures must be two feet above the BFE.

The permit process tracks the number. Plot plans show the regulatory lowest floor elevation, an as-built elevation certificate is due once the lowest floor is complete, and a FEMA elevation certificate (Form 81-31 or equivalent) must be filed before a certificate of occupancy. Under § 25-31(b)1.l, a lot removed from the SFHA by a LOMR-F must still meet the community's freeboard elevation.