Radon in South Carolina

About 1 in 6 homes tested in South Carolina were at or above the EPA action level of 4 pCi/L.

60%22%18%

15,855 homes tested, 2008–2017

The line marks the EPA action level, 4 pCi/L.

The EPA puts 1 of South Carolina's 46 counties in Zone 1, its highest radon category, 8 in Zone 2 and 37 in Zone 3.

Every county in South Carolina

Sorted by the share of homes tested at or above 4 pCi/L. Select a county for local details and costs.

County	Homes tested	At or above 4	Median	EPA zone
Oconee County		43%	3.3 pCi/L	2
Edgefield County	10 tests	–	–	3
Pickens County		24%	1.8 pCi/L	2
Abbeville County		23%	1.8 pCi/L	2
Chester County		22%	1.1 pCi/L	3
Greenville County		20%	1.7 pCi/L	1
Spartanburg County		19%	1.7 pCi/L	2
Saluda County	11 tests	–	–	3
Newberry County		16%	1.1 pCi/L	3
Laurens County		14%	1.3 pCi/L	2
Cherokee County		14%	1.6 pCi/L	2
Lancaster County		14%	1.6 pCi/L	3
York County		14%	1.2 pCi/L	2
Aiken County		13%	1.3 pCi/L	3
Lexington County		13%	0.9 pCi/L	3
Sumter County		12%	1.3 pCi/L	3
Anderson County		11%	1.1 pCi/L	2
Colleton County	11 tests	–	–	3
Fairfield County		7%	0.9 pCi/L	3
Greenwood County		7%	1.0 pCi/L	3
Orangeburg County		6%	0.9 pCi/L	3
Bamberg County	5 tests	–	–	3
Kershaw County		5%	0.7 pCi/L	3
Richland County		5%	0.7 pCi/L	3
Dorchester County		5%	1.0 pCi/L	3
Berkeley County		4%	0.7 pCi/L	3
Beaufort County		2%	0.7 pCi/L	3
Charleston County		2%	0.6 pCi/L	3
Horry County		1%	0.6 pCi/L	3
Allendale County	1 tests	–	–	3
Barnwell County	6 tests	–	–	3
Calhoun County	10 tests	–	–	3
Chesterfield County	8 tests	–	–	3
Clarendon County	3 tests	–	–	3
Darlington County		0%	0.6 pCi/L	3
Dillon County	16 tests	–	–	3
Florence County		0%	0.7 pCi/L	3
Georgetown County		0%	0.1 pCi/L	3
Hampton County	3 tests	–	–	3
Jasper County	9 tests	–	–	3
Lee County	3 tests	–	–	3
Marion County	8 tests	–	–	3
Marlboro County	7 tests	–	–	3
McCormick County	10 tests	–	–	3
Union County		0%	1.0 pCi/L	3
Williamsburg County	13 tests	–	–	3

"–" means fewer than 20 tests or no lab data, too few for a reliable figure.

EPA Map of Radon Zones (public domain).
CDC Environmental Public Health Tracking Network, radon tests from labs, 2008–2017. Pre-mitigation tests only.