Radon levels in South Carolina: Low
The model predicts a population-weighted basement average of 1.6 pCi/L across South Carolina's 46 counties - close to the US average of 1.8 pCi/L. Above-ground floors average 0.9 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
1 / 46
EPA Zone 1 counties (2%)
8 / 37
Zone 2 / Zone 3 counties
0
counties predicted ≥ 4 pCi/L
0%
of ZIP codes predicted ≥ 4 pCi/L
South Carolina counties by predicted radon
Sorted highest to lowest predicted basement average. 46 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Oconee County | 2.5 pCi/L | 1.2 | Moderate | EPA Zone 2 | 10 |
| Greenville County | 2.3 pCi/L | 1.4 | Moderate | EPA Zone 1 | 20 |
| Pickens County | 2.2 pCi/L | 1.1 | Moderate | EPA Zone 2 | 8 |
| Cherokee County | 2.2 pCi/L | 1.0 | Moderate | EPA Zone 2 | 5 |
| Spartanburg County | 2.1 pCi/L | 1.1 | Moderate | EPA Zone 2 | 17 |
| Anderson County | 2.0 pCi/L | 0.9 | Low | EPA Zone 2 | 11 |
| Union County | 1.9 pCi/L | 1.1 | Low | EPA Zone 3 | 3 |
| Abbeville County | 1.9 pCi/L | 0.9 | Low | EPA Zone 2 | 6 |
| Laurens County | 1.9 pCi/L | 1.0 | Low | EPA Zone 2 | 8 |
| Greenwood County | 1.8 pCi/L | 0.9 | Low | EPA Zone 3 | 5 |
| Fairfield County | 1.7 pCi/L | 0.9 | Low | EPA Zone 3 | 5 |
| Newberry County | 1.7 pCi/L | 0.9 | Low | EPA Zone 3 | 8 |
| Saluda County | 1.7 pCi/L | 0.8 | Low | EPA Zone 3 | 3 |
| McCormick County | 1.6 pCi/L | 0.8 | Low | EPA Zone 3 | 4 |
| York County | 1.6 pCi/L | 0.8 | Low | EPA Zone 2 | 11 |
| Chester County | 1.6 pCi/L | 0.8 | Low | EPA Zone 3 | 6 |
| Edgefield County | 1.6 pCi/L | 0.9 | Low | EPA Zone 3 | 6 |
| Lancaster County | 1.6 pCi/L | 0.7 | Low | EPA Zone 3 | 4 |
| Calhoun County | 1.6 pCi/L | 0.9 | Low | EPA Zone 3 | 2 |
| Chesterfield County | 1.5 pCi/L | 0.7 | Low | EPA Zone 3 | 8 |
| Lexington County | 1.5 pCi/L | 0.7 | Low | EPA Zone 3 | 13 |
| Clarendon County | 1.5 pCi/L | 0.8 | Low | EPA Zone 3 | 6 |
| Kershaw County | 1.5 pCi/L | 0.6 | Low | EPA Zone 3 | 6 |
| Florence County | 1.5 pCi/L | 0.8 | Low | EPA Zone 3 | 11 |
| Bamberg County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 4 |
| Darlington County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 5 |
| Orangeburg County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 16 |
| Sumter County | 1.4 pCi/L | 0.9 | Low | EPA Zone 3 | 8 |
| Berkeley County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 12 |
| Dillon County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 6 |
| Allendale County | 1.4 pCi/L | 0.9 | Low | EPA Zone 3 | 5 |
| Barnwell County | 1.4 pCi/L | 0.9 | Low | EPA Zone 3 | 3 |
| Dorchester County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 8 |
| Lee County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 4 |
| Marlboro County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 5 |
| Aiken County | 1.4 pCi/L | 0.9 | Low | EPA Zone 3 | 15 |
| Marion County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 4 |
| Hampton County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 6 |
| Beaufort County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 12 |
| Georgetown County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 3 |
| Williamsburg County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 7 |
| Colleton County | 1.3 pCi/L | 0.7 | Low | EPA Zone 3 | 9 |
| Jasper County | 1.3 pCi/L | 0.7 | Low | EPA Zone 3 | 4 |
| Richland County | 1.3 pCi/L | 0.6 | Low | EPA Zone 3 | 14 |
| Horry County | 1.3 pCi/L | 0.6 | Low | EPA Zone 3 | 16 |
| Charleston County | 1.3 pCi/L | 0.7 | Low | EPA Zone 3 | 22 |
South Carolina radon questions
- Is radon high in South Carolina?
- South Carolina's population-weighted predicted basement average is 1.6 pCi/L, close to the US average of 1.8. 0 of its 46 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 5 are in the 2-4 "consider fixing" range and 41 are below 2. 0% of South Carolina ZIP codes are predicted at 4 or higher.
- Which South Carolina county has the highest radon?
- Oconee County has the highest predicted basement average in South Carolina at 2.5 pCi/L (EPA Zone 2). The lowest is Charleston County at 1.3 pCi/L. These are modeled area averages; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in South Carolina?
- 1 of South Carolina's 46 counties (2%) are EPA Zone 1 (highest potential), 8 are Zone 2 and 37 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in South Carolina?
- Yes. Even though South Carolina's predicted average is below 2 pCi/L, the EPA recommends every home be tested - radon varies house to house, and 13.9% of South Carolina ZIP codes are still predicted at 2 pCi/L or higher.
South Carolina radon program
Many states offer free or discounted test kits and keep lists of certified mitigators. Find the South Carolina radon office through the EPA state radon contacts page. Then read how to test and what mitigation costs.