Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Allendale County, South Carolina
EPA puts Allendale County in Zone 3, its lowest radon zone, and only 1 radon test from it is 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
Nearest county
13.3%
Aiken County, 42 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
- Allendale
- 0.0%
- SC
- 18.5%
Share of land USGS rates moderate or high potential
Tests reported
1
Too few for a share
- Allendale
- 1
- 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 Allendale 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
Allendale County, At a glance
Allendale 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 Allendale County, 2008 to 2017, laboratory
CDC holds 1 reported test for Allendale County over the 2008 to 2017 laboratory totals, a result of 0.1 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Allendale County beside the counties around it is how this page reads it.
What these figures count
Only 1 test was reported to CDC for Allendale 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).
Allendale County, Compared
Allendale County radon figures, compared
Calculated by Radon411CDC's largest figure for Allendale County rests on 1 test over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 100.0 points and no rank or comparison is drawn from it. Results reached as high as 0.1 pCi/L, with a middle value of 0.1 pCi/L.
The nearest counties with a figure are Aiken County (42 miles away) at 13.3%, Orangeburg County (45 miles away) at 5.7% and Beaufort County (55 miles away) at 2.0%. 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 Allendale 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.
Allendale County, Geology
The ground under Allendale County
PredictedUSGS's geologic map puts all of Allendale County's mapped land in one class: low radon potential. 98.8% 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 | 98.8% |
| Lower Coastal Plain | Dune, beach, and marine sediments. | Low | 7 | 0.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Allendale County beside the ground around it
Across South Carolina 0.2% of the land is rated high; none of Allendale County's is. None of the 6 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Allendale County, Local resources
Radon testing and mitigation in Allendale 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
Allendale County, Questions
Questions about radon in Allendale County
Are radon levels high in Allendale County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Allendale County, South Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.1 pCi/L. Of the 8 nearest counties with a figure, within 83 miles, the share of tests at or above 4 pCi/L runs from 1.5% to 13.3%.
Which counties border Allendale County?
Allendale County borders 6 counties: Hampton County, SC, Barnwell County, SC, Screven County, GA, Bamberg County, SC, Burke County, GA and Colleton County, SC.
Products
Allendale County, Products
Testing a home in Allendale County
No CDC figure names Allendale County; the nearest county with one, Aiken County (42 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 Allendale 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
Monitor
lüft plug-in radon and indoor air quality monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi, Bluetooth
- App only
First reading: Within 90 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Allendale County, Bordering counties
Counties bordering Allendale County
Calculated by Radon411- Radon levels in Colleton County, SCEPA zone 3
9.1%at or above 4 pCi/L
Median 0.1 pCi/L · 11 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 Hampton County, SCEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 6 tests
- Radon levels in Barnwell County, SCEPA zone 3
0.0%at or above 4 pCi/L
Median 1.9 pCi/L · 6 tests
- Radon levels in Screven County, GAEPA zone 3
0.0%at or above 4 pCi/L
Median 1.0 pCi/L · 3 tests
- Radon levels in Burke County, GAEPA zone 3
0.0%at or above 4 pCi/L
Median 0.9 pCi/L · 4 tests
Allendale County, Cities and towns
Cities and towns in Allendale County
Allendale County has been losing residents: from 7,940 in 2020 to 7,355 on July 1, 2025, a fall of 7.4% by the Census Bureau's estimates. That works out to 18 people per square mile of land. Its largest town, Allendale, has 2,427 residents, 33.0% of the total. Together its 4 incorporated places hold 54.0% of those residents; the other 46.0% live outside any of them. Reported testing is thin here: 1 test over 2008 to 2017, or 0.1 for every 1,000 residents (2025 estimate), where South Carolina as a whole comes to 4.8.
From Allendale to Ulmer, CDC publishes no figure by town: each reads Allendale County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Allendale | 2,427 | −9.4% | 33.0% |
| Fairfax | 1,352 | −9.0% | 18.4% |
| Sycamore | 138 | −8.6% | 1.9% |
| Ulmer | 55 | −11.3% | 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).
Allendale County, Homes
Homes in Allendale County
Of Allendale County's 4,055 homes, 65% are detached houses, against 64% across South Carolina; 25% are mobile homes. The homes are older than South Carolina's as a whole: half were built before 1981 (1991 for South Carolina), and 22% date from before 1960. 65% 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 | Allendale County | South Carolina |
|---|---|---|
| Housing units | 4,055 | 2,401,638 |
| Detached houses | 65% | 64% |
| In buildings of 5 or more | 4% | 13% |
| Mobile homes | 25% | 15% |
| Built before 1960 | 22% | 13% |
| Built since 2000 | 11% | 35% |
| Middle year built | 1981 | 1991 |
| Owner-occupied | 65% | 71% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.