Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Loudon County, Tennessee
EPA puts Loudon County in Zone 1, its highest radon zone, and high results are common there: 40.2% of the 82 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
40.2%
15.3 pts above TN
- Loudon
- 40.2%
- Tennessee
- 24.9%
82 tests, 2023
Median result
3.0pCi/L
Below action level
- Loudon
- 3.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
82
8th of 15 by tests
- Loudon
- 82
- 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
2 of 15
Top quarter
- Loudon
- 40.2%
- Blount
- 50.0%
By share, of 15 with 30+ tests
Read a result for Loudon County
Starts at Loudon County's median, 3.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.0 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. Loudon County's median reported result, 2023.
The data
Loudon County, At a glance
Loudon County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Loudon County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Loudon County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2022 | 31.4% |
| 2023 | 40.2% |
2023: 40.2%. Across these years the share ran from 31.4% to 40.2%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 82 tests reported to CDC for Loudon 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).
Loudon County, Compared
Loudon County radon figures, compared
Calculated by Radon411In Loudon County, about 4 in 10 reported tests in 2023 (33 of 82) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 6.8 points higher. Across 70 Tennessee counties pooled together, 24.9% of tests reached that level, so Loudon County runs 15.3 points above its state.
Of 2 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 17.7% (Knox County) to 50.0% (Blount County). By share, Loudon County is 2nd of 15 Tennessee counties with 30 or more tests for the same period.
Half the tests came in under 3.0 pCi/L and half over it; the single highest reached 35.6 pCi/L. Below the action level, 27 tests (32.9%) came in under 2 pCi/L, against 49.4% statewide, and 22 tests (26.8%) fell between 2 and 4, against 25.7% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 40.2% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 20 tests taken after mitigation in Loudon County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2022, with 306 tests reported; the quietest, 2023, had 82.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Loudon County, Geology
The ground under Loudon County
PredictedUSGS's geologic map puts all of Loudon County's mapped land in one class: high radon potential. All of it lies in the area the map calls Ridge and Valley, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Ridge and Valley | Paleozoic sandstone and cherty dolostone. | High | 14 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Loudon County beside the ground around it
Loudon County has more high-potential ground than Tennessee as a whole: 100% of its land against 47.2%. Of the 5 counties that border it, none has as large a share of high-potential ground; Knox County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Loudon County, Local resources
Radon testing and mitigation in Loudon 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
Loudon County, Questions
Questions about radon in Loudon County
Are radon levels high in Loudon County?
In 2023, 40.2% of the radon tests reported to CDC for Loudon County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.0 pCi/L. Of 15 Tennessee counties with 30 or more tests for the same period, 1 reported a higher share; pooled, the state comes to 24.9%.
Which counties border Loudon County?
Loudon County borders 5 counties: Roane County, Monroe County, Blount County, McMinn County and Knox County.
Products
Loudon County, Products
Testing a home in Loudon County
In Loudon County, 40.2% of 82 tests reported to CDC in 2023 reached 4 pCi/L, against 24.9% pooled across Tennessee. In Zone 1 the year-round level in Loudon 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
EcoBlu plug-in digital radon monitor with a display
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
Method: Ion chamber
First reading: Within 10 minutes
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Loudon County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Loudon County
Explore
Loudon County, Bordering counties
Counties bordering Loudon County
Calculated by Radon411- Radon levels in Blount CountyEPA zone 1
50.0%at or above 4 pCi/L
Median 3.9 pCi/L · 46 tests · 9.8 points above Loudon County
- Radon levels in McMinn CountyEPA zone 1
25.0%at or above 4 pCi/L
Median 1.6 pCi/L · 4 tests · 15.2 points below Loudon County
- Radon levels in Roane CountyEPA zone 1
20.0%at or above 4 pCi/L
Median 2.2 pCi/L · 20 tests · 20.2 points below Loudon County
- Radon levels in Knox CountyEPA zone 1
17.7%at or above 4 pCi/L
Median 1.8 pCi/L · 203 tests · 22.5 points below Loudon County
- Radon levels in Monroe CountyEPA zone 1
17.6%at or above 4 pCi/L
Median 1.6 pCi/L · 17 tests · 22.6 points below Loudon County
Loudon County, Cities and towns
Cities and towns in Loudon County
Loudon County is growing: the Census Bureau puts it at 63,764 residents on July 1, 2025, up 15.6% from 55,144 in 2020. That works out to 278 people per square mile of land. Farragut, the largest place on its list (25,121 residents in all), extends beyond Loudon County, so no share of the total is worked out for it. Testing is reported here more often than across the state: CDC's 82 reported tests for 2023 come to 1.3 for every 1,000 residents (2025 estimate), against 0.3 for Tennessee.
From Farragut to Philadelphia, CDC publishes no figure by town: each reads Loudon County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Farragutextends beyond Loudon County | 25,121 | +6.6% | Counted whole |
| Lenoir City | 12,530 | +23.9% | 19.7% |
| Loudon | 6,963 | +15.5% | 10.9% |
| Greenback | 1,251 | +14.0% | 2.0% |
| Philadelphia | 704 | +15.2% | 1.1% |
5 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 Loudon County is counted whole, so it has no share.
Loudon County, Homes
Homes in Loudon County
Loudon County is a place of houses on their own lots: 82% of its 25,415 homes are detached single-family houses, against 68% across Tennessee. Half of its homes were built before 1991, close to Tennessee's 1986: 18% date from before 1960 and 35% from 2000 or later. Owners live in 81% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.
| Homes | Loudon County | Tennessee |
|---|---|---|
| Housing units | 25,415 | 3,095,472 |
| Detached houses | 82% | 68% |
| In buildings of 5 or more | 5% | 14% |
| Mobile homes | 7% | 8% |
| Built before 1960 | 18% | 18% |
| Built since 2000 | 35% | 29% |
| Middle year built | 1991 | 1986 |
| Owner-occupied | 81% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.