South Carolina Cities Ranked by Indoor Radon Levels
Measured averages from Airthings devices across South Carolina, USA. Action level: 4 pCi/L — the threshold at which remediation is recommended.
Gaston has the highest measured indoor radon in South Carolina at 6.9 pCi/L, based on Airthings measurements across 54 cities.
Updated September 28, 2026
Highest city
6.9pCi/L
Gaston
South Carolina city average
2.1pCi/L
across 54 cities
Above action level
3/ 54
cities
| # | Location | Avg level | vs action level |
|---|---|---|---|
| 1 | Gaston | 6.9 pCi/L | 1.7× over |
| 2 | Berea | 5.0 pCi/L | 1.3× over |
| 3 | Seneca | 4.1 pCi/L | 1.0× over |
| ✓ Below EPA action level (4 pCi/L) | |||
| 4 | Fountain Inn | 3.9 pCi/L | 1.0× under |
| 5 | Clover | 3.9 pCi/L | 1.0× under |
| 6 | Pickens | 3.7 pCi/L | 0.9× under |
| 7 | Wade Hampton | 3.5 pCi/L | 0.9× under |
| 8 | Greer | 3.5 pCi/L | 0.9× under |
| 9 | Easley | 3.4 pCi/L | 0.8× under |
| 10 | Fort Mill | 3.3 pCi/L | 0.8× under |
| 11 | Central | 3.2 pCi/L | 0.8× under |
| 12 | Spartanburg | 2.9 pCi/L | 0.7× under |
| 13 | Walhalla | 2.7 pCi/L | 0.7× under |
| 14 | Anderson | 2.7 pCi/L | 0.7× under |
| 15 | Duncan | 2.5 pCi/L | 0.6× under |
| 16 | Taylors | 2.5 pCi/L | 0.6× under |
| 17 | Simpsonville | 2.5 pCi/L | 0.6× under |
| 18 | India Hook | 2.5 pCi/L | 0.6× under |
| 19 | Tigerville | 2.4 pCi/L | 0.6× under |
| 20 | Tega Cay | 2.4 pCi/L | 0.6× under |
| 21 | Greenville | 2.3 pCi/L | 0.6× under |
| 22 | Dunean | 2.2 pCi/L | 0.6× under |
| 23 | Lexington | 2.2 pCi/L | 0.6× under |
| 24 | Five Forks | 2.2 pCi/L | 0.5× under |
| 25 | Lake Wylie | 2.0 pCi/L | 0.5× under |
| 26 | Irmo | 2.0 pCi/L | 0.5× under |
| 27 | Mauldin | 1.9 pCi/L | 0.5× under |
| 28 | Rock Hill | 1.9 pCi/L | 0.5× under |
| 29 | Sans Souci | 1.7 pCi/L | 0.4× under |
| 30 | Pendleton | 1.6 pCi/L | 0.4× under |
| 31 | Centerville | 1.6 pCi/L | 0.4× under |
| 32 | Boiling Springs | 1.6 pCi/L | 0.4× under |
| 33 | Gantt | 1.5 pCi/L | 0.4× under |
| 34 | York | 1.5 pCi/L | 0.4× under |
| 35 | New Ellenton | 1.4 pCi/L | 0.4× under |
| 36 | Powdersville | 1.4 pCi/L | 0.3× under |
| 37 | Myrtle Beach | 1.4 pCi/L | 0.3× under |
| 38 | Travelers Rest | 1.2 pCi/L | 0.3× under |
| 39 | Columbia | 1.1 pCi/L | 0.3× under |
| 40 | West Columbia | 1.1 pCi/L | 0.3× under |
| 41 | Northlake | 1.1 pCi/L | 0.3× under |
| 42 | Hilton Head Island | 1.1 pCi/L | 0.3× under |
| 43 | Bluffton | 1.1 pCi/L | 0.3× under |
| 44 | Chapin | 1.1 pCi/L | 0.3× under |
| 45 | Elgin | 1.1 pCi/L | 0.3× under |
| 46 | Forest Acres | 1.0 pCi/L | 0.2× under |
| 47 | Newport | 1.0 pCi/L | 0.2× under |
| 48 | Shell Point | 0.8 pCi/L | 0.2× under |
| 49 | Sangaree | 0.8 pCi/L | 0.2× under |
| 50 | Blythewood | 0.7 pCi/L | 0.2× under |
| 51 | Charleston | 0.6 pCi/L | 0.1× under |
| 52 | Mount Pleasant | 0.5 pCi/L | 0.1× under |
| 53 | North Charleston | 0.3 pCi/L | 0.1× under |
| 54 | Isle of Palms | 0.2 pCi/L | 0.1× under |