Rock Hill, SC Environmental Rules: Flood Elevation Requirements (2026)

Rock Hill requires more than the federal minimum flood protection. City Code § 10-332 defines freeboard as a safety margin above the calculated flood level, and states that the city has a freeboard requirement of two feet above the one percent base flood elevation. Section 10-366 applies that number: new construction or substantial improvement of a residential structure, including manufactured homes, must have its lowest floor elevated no lower than two feet above the base flood elevation, and no basements are permitted. The same two-foot standard applies to nonresidential construction, though commercial and industrial buildings in A-zones may floodproof instead of elevate, provided a registered engineer or architect certifies the structure is watertight below the required elevation and the owner maintains an approved floodproofing maintenance plan with an annual exercise.

Manufactured homes placed in a new or expanded park must be elevated the same two feet above base flood elevation and anchored to resist flotation and lateral movement. Elevated buildings that use the space below the required floor for parking, building access or limited storage must include flood vents, at least two openings on different walls totaling one square inch of net area per square foot of enclosed space, with the lowest opening no higher than one foot above grade. 00 must meet the full elevation or floodproofing standard; cheaper accessory structures get a lighter checklist but must still be anchored and built of flood-resistant material.