South Carolina Radon Levels
1Zone 1 (High)
8Zone 2 (Moderate)
37Zone 3 (Low)
2% of counties in South Carolina are classified as EPA Zone 1 (highest radon potential), meaning predicted average indoor radon levels exceed 4 pCi/L — the EPA action level. The EPA recommends that all homes be tested for radon, regardless of zone classification.
| County | EPA Zone | Risk Level |
|---|---|---|
| Abbeville County | Zone 2 | Moderate Potential |
| Aiken County | Zone 3 | Lowest Potential |
| Allendale County | Zone 3 | Lowest Potential |
| Anderson County | Zone 2 | Moderate Potential |
| Bamberg County | Zone 3 | Lowest Potential |
| Barnwell County | Zone 3 | Lowest Potential |
| Beaufort County | Zone 3 | Lowest Potential |
| Berkeley County | Zone 3 | Lowest Potential |
| Calhoun County | Zone 3 | Lowest Potential |
| Charleston County | Zone 3 | Lowest Potential |
| Cherokee County | Zone 2 | Moderate Potential |
| Chester County | Zone 3 | Lowest Potential |
| Chesterfield County | Zone 3 | Lowest Potential |
| Clarendon County | Zone 3 | Lowest Potential |
| Colleton County | Zone 3 | Lowest Potential |
| Darlington County | Zone 3 | Lowest Potential |
| Dillon County | Zone 3 | Lowest Potential |
| Dorchester County | Zone 3 | Lowest Potential |
| Edgefield County | Zone 3 | Lowest Potential |
| Fairfield County | Zone 3 | Lowest Potential |
| Florence County | Zone 3 | Lowest Potential |
| Georgetown County | Zone 3 | Lowest Potential |
| Greenville County | Zone 1 | Highest Potential |
| Greenwood County | Zone 3 | Lowest Potential |
| Hampton County | Zone 3 | Lowest Potential |
| Horry County | Zone 3 | Lowest Potential |
| Jasper County | Zone 3 | Lowest Potential |
| Kershaw County | Zone 3 | Lowest Potential |
| Lancaster County | Zone 3 | Lowest Potential |
| Laurens County | Zone 2 | Moderate Potential |
| Lee County | Zone 3 | Lowest Potential |
| Lexington County | Zone 3 | Lowest Potential |
| McCormick County | Zone 3 | Lowest Potential |
| Marion County | Zone 3 | Lowest Potential |
| Marlboro County | Zone 3 | Lowest Potential |
| Newberry County | Zone 3 | Lowest Potential |
| Oconee County | Zone 2 | Moderate Potential |
| Orangeburg County | Zone 3 | Lowest Potential |
| Pickens County | Zone 2 | Moderate Potential |
| Richland County | Zone 3 | Lowest Potential |
| Saluda County | Zone 3 | Lowest Potential |
| Spartanburg County | Zone 2 | Moderate Potential |
| Sumter County | Zone 3 | Lowest Potential |
| Union County | Zone 3 | Lowest Potential |
| Williamsburg County | Zone 3 | Lowest Potential |
| York County | Zone 2 | Moderate Potential |