Aiken County, SC Building Setbacks & Zoning: Lot Coverage Limits (2026)

Table 2 of the Aiken County zoning ordinance, referenced in Section 24-2.5(a), lists a "Maximum Impervious Surface Area Ratio" row that caps the percentage of each lot that pavement, driveways, and buildings may cover. The most restrictive limits apply to low-density residential and rural districts: the Residential Single-Family Conservation (RC) and Residential-Horse 5 (RH5) Districts are capped at 35 percent, the Residential Multifamily Development (RD) District at 45 percent, and the Residential Limited Mixed Use (RM), Rural Community (RUC), Residential-Horse Business (RH5B), and Rural Residential Commercial (RRC) Districts at 55 percent.

Commercial and mixed-use districts allow substantially more coverage. The Office-Residential (OR) District is capped at 55 percent, while the Neighborhood Commercial (NC), Urban Development (UD), Limited Development (LD), and Industrial (IND) Districts are all capped at 70 percent, the highest ratio among primary districts. The Highway Corridor Overlay (HCO) District, which applies along the county's main commercial corridors such as Whiskey Road and Atomic Road, carries the single highest limit in the table at 75 percent. The Rural District (RUD) is marked "NA," meaning the ratio does not apply there, and the Agricultural Preservation (AP) District sits at 55 percent, consistent with its mixed residential and small-scale commercial uses.

Because the ratio caps total lot coverage rather than just building footprint, it governs driveways, parking lots, patios, and accessory structures together with the principal building. A property owner proposing to exceed the applicable ratio needs either a variance from the Board of Appeals or a rezoning to a district with a higher allowance.