Catoosa County, GA Environmental Rules: Flood Elevation Requirements (2026)

Section 3.08.04.B(1) of the UDC sets the county's core freeboard standard: where base flood elevation data are available, new construction and/or substantial improvement of any structure or manufactured home shall have the lowest floor, including basement, elevated no lower than two and seven-tenths feet above the base flood elevation. All mechanical, electrical, plumbing and HVAC equipment must be elevated to that same 2.7-foot mark. If a builder instead uses solid perimeter foundation walls to raise the structure, Section 3.08.04.A(4) requires flood vents sized to at least one square inch of opening for every square foot of enclosed area below the lowest floor, with the lowest opening no higher than one foot above grade.

Manufactured homes get their own version of the standard under Section 3.08.04.B(3): the lowest floor must clear 2.7 feet above base flood elevation, or the home's chassis must sit on reinforced piers at least 36 inches above grade, whichever is higher, and the home must be anchored against flotation and lateral movement. Where FEMA hasn't published base flood elevation data for a stream, Section 3.08.04.C(3) falls back to a flat three-foot elevation above the highest adjacent grade instead of the 2.7-foot freeboard. In shallow-flooding AO zones, Section 3.08.04.D requires elevation to the flood depth number on the map or, absent a posted number, at least three feet above the highest adjacent grade.

The Stormwater Director certifies and permanently records the as-built lowest-floor elevation for every permit under Section 3.08.03.C(5), and Section 3.08.02.H's $1,000 fine and 30-day jail penalty applies to noncompliance.