Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Barnwell County, South Carolina
EPA puts Barnwell County in Zone 3, its lowest radon zone, and only 6 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
13.3%
Aiken County
- Aiken
- 13.3%
- Orangeburg
- 5.7%
2 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
13.3%
Aiken County, 22 miles
- Aiken
- 13.3%
- SC
- 19.4%
Share at 4+ pCi/L, 241 tests, 2008 to 2017
Ground above low
None
18.5 pts below SC
- Barnwell
- 0.0%
- SC
- 18.5%
Share of land USGS rates moderate or high potential
Tests reported
6
Too few for a share
- Barnwell
- 6
- 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 Barnwell 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
Barnwell County, At a glance
Barnwell 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 Barnwell County, 2008 to 2017, laboratory
CDC holds 6 reported tests for Barnwell County over the 2008 to 2017 laboratory totals, with a median of 1.9 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Barnwell County beside the counties around it is how this page reads it.
What these figures count
Only 6 tests were reported to CDC for Barnwell 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).
Barnwell County, Compared
Barnwell County radon figures, compared
Calculated by Radon411CDC's largest figure for Barnwell County rests on 6 tests over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 16.7 points and no rank or comparison is drawn from it. Results reached as high as 3.6 pCi/L, with a middle value of 1.9 pCi/L.
Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Aiken County reported the largest share at or above 4 pCi/L, 13.3%, and Orangeburg County the smallest, 5.7%. Farther out, Lexington County (45 miles away) at 12.5%, Richland County (60 miles away) at 4.9% and Dorchester County (61 miles away) at 4.8% 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 Barnwell 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.
Barnwell County, Geology
The ground under Barnwell County
PredictedUSGS's geologic map puts all of Barnwell 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 | 99.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Barnwell County beside the ground around it
Across South Carolina 0.2% of the land is rated high; none of Barnwell County's is. None of the 5 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Barnwell County, Local resources
Radon testing and mitigation in Barnwell 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
Barnwell County, Questions
Questions about radon in Barnwell County
Are radon levels high in Barnwell County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Barnwell County, South Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.9 pCi/L. Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Aiken County reported the largest share at or above 4 pCi/L, 13.3%, and Orangeburg County the smallest, 5.7%.
Which counties border Barnwell County?
Barnwell County borders 5 counties: Aiken County, SC, Allendale County, SC, Bamberg County, SC, Burke County, GA and Orangeburg County, SC.
Products
Barnwell County, Products
Testing a home in Barnwell County
No CDC figure names Barnwell County; the nearest county with one, Aiken County (22 miles away), reported 13.3% 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 Barnwell County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Monitor
RadonEye RD200 plug-in continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- 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
Barnwell County, Bordering counties
Counties bordering Barnwell County
Calculated by Radon411- Radon levels in Aiken County, SCEPA zone 3
13.3%at or above 4 pCi/L
Median 1.3 pCi/L · 241 tests
- Radon levels in Orangeburg County, SCEPA zone 3
5.7%at or above 4 pCi/L
Median 0.9 pCi/L · 53 tests
- Radon levels in Bamberg County, SCEPA zone 3
5.0%at or above 4 pCi/L
Median 1.0 pCi/L · 20 tests
- Radon levels in Allendale County, SCEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 1 test
- Radon levels in Burke County, GAEPA zone 3
0.0%at or above 4 pCi/L
Median 0.9 pCi/L · 4 tests
Barnwell County, Cities and towns
Cities and towns in Barnwell County
Barnwell County's population has barely moved since 2020: 20,653 residents on July 1, 2025 against 20,580 then, by the Census Bureau's estimates. That works out to 38 people per square mile of land. Its largest town, Barnwell, has 4,619 residents, 22.4% of the total. Together its 7 incorporated places hold 50.4% of those residents; the other 49.6% live outside any of them. Reported testing is thin here: 6 tests over 2008 to 2017, or 0.3 for every 1,000 residents (2025 estimate), where South Carolina as a whole comes to 4.8.
From Barnwell to Elko, CDC publishes no figure by town: each reads Barnwell County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Barnwell | 4,619 | −0.6% | 22.4% |
| Williston | 2,898 | +0.3% | 14.0% |
| Blackville | 1,925 | −0.1% | 9.3% |
| Hilda | 425 | +1.2% | 2.1% |
| Snelling | 251 | Level | 1.2% |
| Kline | 144 | −0.7% | 0.7% |
| Elko | 140 | +2.2% | 0.7% |
7 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).
Barnwell County, Homes
Homes in Barnwell County
Of Barnwell County's 9,901 homes, 58% are detached houses, against 64% across South Carolina; 32% are mobile homes. Half of its homes were built before 1984, close to South Carolina's 1991: 17% date from before 1960 and 17% from 2000 or later. 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 | Barnwell County | South Carolina |
|---|---|---|
| Housing units | 9,901 | 2,401,638 |
| Detached houses | 58% | 64% |
| In buildings of 5 or more | 3% | 13% |
| Mobile homes | 32% | 15% |
| Built before 1960 | 17% | 13% |
| Built since 2000 | 17% | 35% |
| Middle year built | 1984 | 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.