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

Article 7-8-10 defines "base flood elevation" as the highest anticipated water surface elevation during the base flood, itself the flood with a one percent annual chance of occurring, based on Flood Insurance Studies dated December 16, 2008, November 2, 2012, March 4, 2013 and October 5, 2018, plus any FEMA-approved engineering study. Section 7-8-10-050(B) sets the actual freeboard standard: new construction and substantial improvements of residential and non-residential buildings must have the lowest floor, including any basement, elevated no lower than three feet above the base flood elevation or one foot above the future-conditions flood elevation, whichever is higher, once the general standards in Sections 7-8-10-040(C), (D) and (E) are met.

Non-residential structures may floodproof to that same level instead of elevating, but a licensed engineer or architect must certify the design and file a FEMA floodproofing certificate. Enclosed areas below the lowest floor must have flood vents totaling at least one square inch per square foot of enclosed area, with the bottom of each opening no higher than one foot above grade. Manufactured homes and recreational vehicles face the same three-foot/one-foot elevation standard. 00 of coverage; appeals go to Cobb County Superior Court.