Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Darlington County, South Carolina
EPA puts Darlington County in Zone 3, its lowest radon zone, and only 28 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
5.0%
Kershaw County
- Kershaw
- 5.0%
- Florence
- 0.0%
2 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
0.0%
Florence County, 26 miles
- Florence
- 0.0%
- SC
- 19.4%
Share at 4+ pCi/L, 59 tests, 2008 to 2017
Ground above low
None
18.5 pts below SC
- Darlington
- 0.0%
- SC
- 18.5%
Share of land USGS rates moderate or high potential
Tests reported
28
Too few for a share
- Darlington
- 28
- Needed
- 30
2008 to 2017, laboratory
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for Darlington County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
Darlington County, At a glance
Darlington County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Darlington County, 2008 to 2017, laboratory
CDC holds 28 reported tests for Darlington County over the 2008 to 2017 laboratory totals, with a median of 0.6 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Darlington County beside the counties around it is how this page reads it.
What these figures count
Only 28 tests were reported to CDC for Darlington County over 2008 to 2017 (laboratory totals), and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Darlington County, Compared
Darlington County radon figures, compared
Calculated by Radon411CDC's largest figure for Darlington County rests on 28 tests over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 3.6 points and no rank or comparison is drawn from it. Results reached as high as 2.8 pCi/L, with a middle value of 0.6 pCi/L.
Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Kershaw County reported the largest share at or above 4 pCi/L, 5.0%, and Florence County the smallest, 0.0%. Farther out, Sumter County (38 miles away) at 11.9%, Lancaster County (49 miles away) at 13.6% and Richland County (58 miles away) at 4.9% have figures too. Pooled across 46 South Carolina counties, 19.4% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Oconee County reported the highest share (42.6%) and Florence County the lowest (0.0%). EPA's 1993 map puts Darlington County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 100% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Darlington County, Geology
The ground under Darlington County
PredictedUSGS's geologic map puts all of Darlington County's mapped land in one class: low radon potential. All of it lies in the area the map calls Upper and Middle Coastal Plain, to which USGS gives a radon index of 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Upper and Middle Coastal Plain | Tertiary coastal plain sandy and silty sediments and marsh deposits. | Low | 8 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Darlington County beside the ground around it
Across South Carolina 0.2% of the land is rated high; none of Darlington County's is. Of the 5 counties that border it, 2 have more moderate-potential ground, Kershaw County the most at 11.3%.
The map rates the ground, not the air in any home.
Local help
Darlington County, Local resources
Radon testing and mitigation in Darlington County
- South Carolina Radon ProgramSouth Carolina Radon Program, run by South Carolina Department of Environmental Services, offers free or discounted test kits, and answers questions about testing and mitigation in South Carolina.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The South Carolina Radon Program offers free short-term radon test kits to South Carolina homeowners, subject to availability.
- Compare kits
- Professionals in South Carolina2 professionals are listed in South Carolina.
What South Carolina's program says
- Phone
- 1-800-768-0362
- radon@des.sc.gov
What it means
Darlington County, Questions
Questions about radon in Darlington County
Are radon levels high in Darlington County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Darlington County, South Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.6 pCi/L. Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Kershaw County reported the largest share at or above 4 pCi/L, 5.0%, and Florence County the smallest, 0.0%.
Which counties border Darlington County?
Darlington County borders 5 counties: Chesterfield County, Florence County, Marlboro County, Lee County and Kershaw County.
Products
Darlington County, Products
Testing a home in Darlington County
No CDC figure names Darlington County; the nearest county with one, Florence County (26 miles away), reported 0.0% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Darlington County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorAranet
Radon One battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Darlington County, Bordering counties
Counties bordering Darlington County
Calculated by Radon411- Radon levels in Kershaw CountyEPA zone 3
5.0%at or above 4 pCi/L
Median 0.7 pCi/L · 60 tests
- Radon levels in Chesterfield CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.6 pCi/L · 10 tests
- Radon levels in Florence CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.7 pCi/L · 59 tests
- Radon levels in Marlboro CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.9 pCi/L · 7 tests
- Radon levels in Lee CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.1 pCi/L · 3 tests
Darlington County, Cities and towns
Cities and towns in Darlington County
Darlington County's population has barely moved since 2020: 62,888 residents on July 1, 2025 against 62,853 then, by the Census Bureau's estimates. That works out to 112 people per square mile of land. No town dominates: Hartsville, the largest, has 7,374 residents, 11.7% of the total. Together its 4 incorporated places hold 23.4% of those residents; the other 76.6% live outside any of them. Reported testing is thin here: 28 tests over 2008 to 2017, or 0.4 for every 1,000 residents (2025 estimate), where South Carolina as a whole comes to 4.8.
From Hartsville to Society Hill, CDC publishes no figure by town: each reads Darlington County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hartsville | 7,374 | −0.9% | 11.7% |
| Darlington | 6,075 | −2.0% | 9.7% |
| Lamar | 862 | +0.7% | 1.4% |
| Society Hill | 428 | −1.4% | 0.7% |
4 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Darlington County, Homes
Homes in Darlington County
Of Darlington County's 29,645 homes, 64% are detached houses, against 64% across South Carolina; 29% are mobile homes. The homes are older than South Carolina's as a whole: half were built before 1983 (1991 for South Carolina), and 18% date from before 1960. 71% of occupied homes are lived in by their owner (South Carolina: 71%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Darlington County | South Carolina |
|---|---|---|
| Housing units | 29,645 | 2,401,638 |
| Detached houses | 64% | 64% |
| In buildings of 5 or more | 3% | 13% |
| Mobile homes | 29% | 15% |
| Built before 1960 | 18% | 13% |
| Built since 2000 | 19% | 35% |
| Middle year built | 1983 | 1991 |
| Owner-occupied | 71% | 71% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.