Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
Locations and reports
Radon Levels in Unicoi County, Tennessee
EPA puts Unicoi County in Zone 2, its middle radon zone, and only 2 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
37.1%
3.8 pts above TN
- Unicoi
- 37.1%
- Tennessee
- 33.3%
132 tests, 2008 to 2017
Median result
2.8pCi/L
Below action level
- Unicoi
- 2.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
132
39th of 80 by tests
- Unicoi
- 132
- Davidson
- 5,592
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Tennessee
25 of 80
Middle half
- Unicoi
- 37.1%
- Jefferson
- 56.8%
By share, of 80 with 30+ tests
Read a result for Unicoi County
Starts at Unicoi County's median, 2.8 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.8 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Unicoi County's median reported result, 2008 to 2017.
The data
Unicoi County, At a glance
Unicoi County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Unicoi County is a
USGS geologic potential: High across 64% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Unicoi County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2022 | 20.0% |
| 2023 | 50.0% |
2023: 50.0%. Across these years the share ran from 20.0% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 2 tests were reported to CDC for Unicoi County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Unicoi County, Compared
Unicoi County radon figures, compared
Calculated by Radon411In Unicoi County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (49 of 132) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 1.4 points higher. Across 95 Tennessee counties pooled together, 33.3% of tests reached that level, so Unicoi County runs 3.8 points above its state.
The newest figure, in 2023, counts only 2 tests (50.0% at or above 4 pCi/L), too few to compare, so this reading uses the 132-test figure.
Of 6 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 16.7% (Madison County, NC) to 49.6% (Washington County). By share, Unicoi County is 25th of 80 Tennessee counties with 30 or more tests for the same period.
Half the tests came in under 2.8 pCi/L and half over it; the single highest reached 42.0 pCi/L. Below the action level, 47 tests (35.6%) came in under 2 pCi/L, against 42.4% statewide, and 36 tests (27.3%) fell between 2 and 4, against 24.3% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 37.1% share point the same way here. USGS geology rates 64% of the county's land high radon potential. CDC also counts 6 tests taken after mitigation in Unicoi County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2022, with 15 tests reported; the quietest, 2023, had 2.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Unicoi County, Geology
The ground under Unicoi County
PredictedUSGS's geologic map splits Unicoi County: 64.5% of its land is high radon potential and 35.6% moderate. The map puts 64.5% of Unicoi County in the area it calls Ridge and Valley and 34.7% in Unaka Mountains, with one smaller area beside them. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Ridge and Valley | Paleozoic sandstone and cherty dolostone. | High | 14 | 64.5% |
| Unaka Mountains | Precambrian and Paleozoic siltstone, sandstone, conglomerate, quartzite, phyllite, gneiss, granite, and metamorphosed volcanic rock. | Moderate | 11 | 34.7% |
| Blue Ridge | Granite, pegmatite, monazite, schist, and gneiss. | Moderate | 10 | 0.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Unicoi County beside the ground around it
Unicoi County has more high-potential ground than Tennessee as a whole: 64.5% of its land against 47.2%. Of the 6 counties that border it, 2 have more high-potential ground, Washington County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Unicoi County, Local resources
Radon testing and mitigation in Unicoi County
- Tennessee Radon ProgramTennessee Radon Program, run by Department of Environment & Conservation, offers free or discounted test kits, and answers questions about testing and mitigation in Tennessee.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The Tennessee Radon Program provides free radon test kits and information assistance to residents, while also providing training opportunities to radon professionals across the state.
- Compare kits
- Professionals in Tennessee1 professional is listed in Tennessee.
What Tennessee's program says
- Phone
- 1-800-232-1139
- TDEC.Radon@tn.gov
What it means
Unicoi County, Questions
Questions about radon in Unicoi County
Are radon levels high in Unicoi County?
In 2023, 50.0% of the radon tests reported to CDC for Unicoi County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.9 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 24 reported a higher share; pooled, the state comes to 33.3%.
Which counties border Unicoi County?
Unicoi County borders 6 counties: Washington County, TN, Yancey County, NC, Madison County, NC, Mitchell County, NC, Carter County, TN and Greene County, TN.
Products
Unicoi County, Products
Testing a home in Unicoi County
In Unicoi County, 37.1% of 132 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Unicoi County; a long-term test tells the year-round average.
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
EcoQube Wi-Fi continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi
- App only
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
Unicoi County, Bordering counties
Counties bordering Unicoi County
Calculated by Radon411- Radon levels in Washington County, TNEPA zone 1
49.6%at or above 4 pCi/L
Median 3.9 pCi/L · 1,590 tests · 12.5 points above Unicoi County
- Radon levels in Carter County, TNEPA zone 2
47.2%at or above 4 pCi/L
Median 3.7 pCi/L · 345 tests · 10.1 points above Unicoi County
- Radon levels in Greene County, TNEPA zone 1
46.0%at or above 4 pCi/L
Median 3.6 pCi/L · 385 tests · 8.9 points above Unicoi County
- Radon levels in Yancey County, NCEPA zone 2
31.0%at or above 4 pCi/L
Median 1.9 pCi/L · 290 tests · 6.1 points below Unicoi County
- Radon levels in Mitchell County, NCEPA zone 1
28.6%at or above 4 pCi/L
Median 2.1 pCi/L · 433 tests · 8.5 points below Unicoi County
- Radon levels in Madison County, NCEPA zone 2
16.7%at or above 4 pCi/L
Median 1.3 pCi/L · 228 tests · 20.4 points below Unicoi County
Unicoi County, Cities and towns
Cities and towns in Unicoi County
Unicoi County's population has barely moved since 2020: 17,856 residents on July 1, 2025 against 17,873 then, by the Census Bureau's estimates. That works out to 96 people per square mile of land. Its largest town, Erwin, has 6,019 residents, 33.7% of the total. Together its 2 incorporated places hold 55.3% of those residents; the other 44.7% live outside any of them. Testing is reported here more often than across the state: CDC's 132 reported tests for 2008 to 2017 come to 7.4 for every 1,000 residents (2025 estimate), against 4.2 for Tennessee.
From Erwin to Unicoi, CDC publishes no figure by town: each reads Unicoi County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Erwin | 6,019 | −0.7% | 33.7% |
| Unicoi | 3,861 | +1.4% | 21.6% |
2 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).
Unicoi County, Homes
Homes in Unicoi County
Of Unicoi County's 8,740 homes, 69% are detached houses, against 68% across Tennessee; 18% are mobile homes. The homes are older than Tennessee's as a whole: half were built before 1976 (1986 for Tennessee), and 30% date from before 1960. 73% of occupied homes are lived in by their owner (Tennessee: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Unicoi County | Tennessee |
|---|---|---|
| Housing units | 8,740 | 3,095,472 |
| Detached houses | 69% | 68% |
| In buildings of 5 or more | 6% | 14% |
| Mobile homes | 18% | 8% |
| Built before 1960 | 30% | 18% |
| Built since 2000 | 16% | 29% |
| Middle year built | 1976 | 1986 |
| Owner-occupied | 73% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.