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

Columbia County's flood damage prevention ordinance sets the freeboard standard for the unincorporated county. Where base flood elevation data are available, new construction or substantial improvement of any residential structure must have the lowest floor, including any basement, elevated no lower than three feet above the base flood elevation, per Sec. 42-44(b)(1). Nonresidential buildings face the same three-foot elevation standard, but Sec. 42-44(b)(2) allows floodproofing in lieu of elevation in A1-30, AE or AH zones, provided the structure below the required elevation is watertight with substantially impermeable walls able to resist hydrostatic and hydrodynamic loads; a registered professional engineer or architect must certify the design.

Manufactured homes on individual lots or in new or expanded parks face the identical three-foot lowest-floor standard under Sec. 42-44(b)(4)a, while homes in existing manufactured home parks may instead sit on reinforced piers at least 36 inches above grade under Sec. 2. Where no base flood elevation data exist for a residential single-lot development, Sec. 42-44(c)(3) still requires the lowest floor elevated no less than three feet above the highest adjacent grade at the site, or one foot above estimated base flood elevation in a studied A-Zone.

Applicants must file a land disturbance permit under Sec. 42-42 with elevation certifications from a registered land surveyor, engineer or architect, then submit an as-built lowest-floor certification to the administrator immediately after the floor or floodproofing is completed. Deficiencies found on review must be corrected before further work proceeds, and unsubmitted surveys are cause for a stop-work order. Elevated buildings with enclosed areas below the lowest floor must provide flood vents totaling at least one square inch of net opening per square foot of enclosed area, with openings no higher than one foot above grade, under Sec. 42-44(b)(3)a.