Acworth, GA Environmental Rules: Flood Elevation Requirements (2026)

Acworth defines "base flood elevation" in § 50-78 as "the highest water surface elevation anticipated at any given point during the base flood," with the base flood meaning the 100-year, one-percent-annual-chance flood. Section 50-102(1)a builds Acworth's local freeboard on top of that federal baseline: once a residential project has satisfied the general floodplain-encroachment standards of §§ 50-93, 50-94 and 50-95, all new construction must have the lowest floor, including basement, elevated no lower than three feet above the base flood elevation, or one foot above the future-conditions flood elevation, whichever is higher.

That three-foot figure is a local add-on above the National Flood Insurance Program minimum, and it applies to substantial improvements of existing homes as well as new construction. Non-residential buildings get a lighter one-foot standard under § 50-102(2), with a flood-proofing alternative to elevation if a professional engineer or architect certifies the design. Solid perimeter foundation walls used to reach the required elevation must carry flood-vent openings sized under § 50-101(5): a minimum of two openings totaling one square inch of net area per square foot of enclosed area below the lowest floor, with the bottom of every opening no higher than one foot above grade.

The public works department administers the article and reviews the as-built elevation certificate required after floor completion under § 50-87, and can hold up further construction if the certification shows a deficiency.