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
Locations and reports
Radon Levels in Blount County, Tennessee
EPA puts Blount County in Zone 1, its highest radon zone, and high results are common there: 50.0% of the 46 radon tests reported to CDC (2023) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
50.0%
25.1 pts above TN
- Blount
- 50.0%
- Tennessee
- 24.9%
46 tests, 2023
Median result
3.9pCi/L
Below action level
- Blount
- 3.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
46
11th of 15 by tests
- Blount
- 46
- Hamblen
- 594
Reported to CDC before any fix, 2023
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Tennessee
1 of 15
Top quarter
- Blount
- 50.0%
- Blount
- 50.0%
By share, of 15 with 30+ tests
Read a result for Blount County
Starts at Blount County's median, 3.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.9 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. Blount County's median reported result, 2023.
The data
Blount County, At a glance
Blount County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Blount County in
USGS geologic potential: High across 63% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Blount County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2022 | 29.0% |
| 2023 | 50.0% |
2023: 50.0%. Across these years the share ran from 29.0% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 46 tests reported to CDC for Blount County over 2023, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Blount County, Compared
Blount County radon figures, compared
Calculated by Radon411More than half: 50.0% of the 46 radon tests reported to CDC for Blount County in 2023 read at least 4 pCi/L. That places it 1st of 15 Tennessee counties with 30 or more tests for the same period. That is 25.1 points above the 24.9% pooled from 70 Tennessee counties.
The median result, 3.9 pCi/L, sits between 2 and EPA's 4 pCi/L action level, and the top reported result was 39.6 pCi/L. The rest split 28.3% under 2 pCi/L and 21.7% from 2 to 4 (Tennessee: 49.4% and 25.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 50.0% share point the same way here.
No bordering county with a figure for the same period reported a higher share; the closest is Loudon County at 40.2%, the lowest Knox County at 17.7%. Statewide for the same period, Loudon County reported the highest share (40.2%) and Hamilton County the lowest (2.4%).
The busiest year on file was 2022, with 321 tests reported; the quietest, 2023, had 46.
Nationally, every county with a figure for the same period pools to 33.4%; Blount County sits 16.6 points above it. CDC also counts 16 tests taken after mitigation in Blount County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Blount County, Geology
The ground under Blount County
PredictedUSGS's geologic map splits Blount County: 63.2% of its land is high radon potential and 36.8% moderate. The map puts 63.2% of Blount County in the area it calls Ridge and Valley and 36.5% in Unaka Mountains. 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 | 63.2% |
| Unaka Mountains | Precambrian and Paleozoic siltstone, sandstone, conglomerate, quartzite, phyllite, gneiss, granite, and metamorphosed volcanic rock. | Moderate | 11 | 36.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Blount County beside the ground around it
Blount County has more high-potential ground than Tennessee as a whole: 63.2% of its land against 47.2%. Of the 6 counties that border it, 2 have more high-potential ground, Knox County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Blount County, Local resources
Radon testing and mitigation in Blount 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
Blount County, Questions
Questions about radon in Blount County
Are radon levels high in Blount County?
In 2023, 50.0% of the radon tests reported to CDC for Blount County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.9 pCi/L. Of 15 Tennessee counties with 30 or more tests for the same period, none reported a higher share; pooled, the state comes to 24.9%.
Which counties border Blount County?
Blount County borders 6 counties: Swain County, NC, Knox County, TN, Loudon County, TN, Sevier County, TN, Monroe County, TN and Graham County, NC.
Products
Blount County, Products
Testing a home in Blount County
In Blount County, 50.0% of 46 tests reported to CDC in 2023 reached 4 pCi/L, against 24.9% pooled across Tennessee. In Zone 1 the year-round level in Blount County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
Monitor
Corentium Home 2 battery digital radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Blount County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Blount County
Explore
Blount County, Bordering counties
Counties bordering Blount County
Calculated by Radon411- Radon levels in Loudon County, TNEPA zone 1
40.2%at or above 4 pCi/L
Median 3.0 pCi/L · 82 tests · 9.8 points below Blount County
- Radon levels in Sevier County, TNEPA zone 2
33.3%at or above 4 pCi/L
Median 2.3 pCi/L · 18 tests · 16.7 points below Blount County
- Radon levels in Knox County, TNEPA zone 1
17.7%at or above 4 pCi/L
Median 1.8 pCi/L · 203 tests · 32.3 points below Blount County
- Radon levels in Monroe County, TNEPA zone 1
17.6%at or above 4 pCi/L
Median 1.6 pCi/L · 17 tests · 32.4 points below Blount County
- Radon levels in Swain County, NCEPA zone 2
No CDC figure for 2023; its page reads it against its own neighbours.
- Radon levels in Graham County, NCEPA zone 2
No CDC figure for 2023; its page reads it against its own neighbours.
Blount County, Cities and towns
Cities and towns in Blount County
Blount County is growing: the Census Bureau puts it at 143,820 residents on July 1, 2025, up 6.0% from 135,666 in 2020. That works out to 257 people per square mile of land. Its largest town, Maryville, has 32,442 residents, 22.6% of the total. CDC's 46 reported tests for 2023 work out to 0.3 per 1,000 residents (2025 estimate), close to Tennessee's 0.3.
From Maryville to Townsend, CDC publishes no figure by town: each reads Blount County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Maryville | 32,442 | +1.4% | 22.6% |
| Alcoa | 13,689 | +24.6% | 9.5% |
| Louisville | 4,562 | +4.2% | 3.2% |
| Vonoreextends beyond Blount County | 1,715 | +8.3% | Counted whole |
| Friendsville | 916 | +2.8% | 0.6% |
| Rockford | 842 | −0.5% | 0.6% |
| Townsend | 640 | +16.8% | 0.4% |
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). A place that extends beyond Blount County is counted whole, so it has no share.
Blount County, Homes
Homes in Blount County
Blount County is a place of houses on their own lots: 77% of its 60,912 homes are detached single-family houses, against 68% across Tennessee. Half of its homes were built before 1988, close to Tennessee's 1986: 18% date from before 1960 and 31% from 2000 or later. Owners live in 77% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.
| Homes | Blount County | Tennessee |
|---|---|---|
| Housing units | 60,912 | 3,095,472 |
| Detached houses | 77% | 68% |
| In buildings of 5 or more | 7% | 14% |
| Mobile homes | 11% | 8% |
| Built before 1960 | 18% | 18% |
| Built since 2000 | 31% | 29% |
| Middle year built | 1988 | 1986 |
| Owner-occupied | 77% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.