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 Rhea County, Tennessee
EPA puts Rhea County in Zone 3, its lowest 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
26.7%
6.6 pts below TN
- Rhea
- 26.7%
- Tennessee
- 33.3%
45 tests, 2008 to 2017
Median result
2.4pCi/L
Below action level
- Rhea
- 2.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
45
67th of 80 by tests
- Rhea
- 45
- Davidson
- 5,592
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Tennessee
45 of 80
Middle half
- Rhea
- 26.7%
- Jefferson
- 56.8%
By share, of 80 with 30+ tests
Read a result for Rhea County
Starts at Rhea County's median, 2.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.4 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. Rhea County's median reported result, 2008 to 2017.
The data
Rhea County, At a glance
Rhea County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: High across 61% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Rhea County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2022 | 0.0% |
| 2023 | 50.0% |
2023: 50.0%. Across these years the share ran from 0.0% 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 Rhea 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).
Rhea County, Compared
Rhea County radon figures, compared
Calculated by Radon411Rhea County's 45 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.4 pCi/L and a maximum of 41.6 pCi/L, and 26.7% reached 4 pCi/L. Tennessee as a whole (95 Tennessee counties, pooled) comes to 33.3%: 6.6 points higher than here.
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 45-test figure.
Among its state's counties it ranks 45th of 80 Tennessee counties with 30 or more tests for the same period. Statewide for the same period, Jefferson County reported the highest share (56.8%) and Chester County the lowest (0.0%).
Below the action level, 22 tests (48.9%) came in under 2 pCi/L, against 42.4% statewide, and 11 tests (24.4%) fell between 2 and 4, against 24.3% statewide. The busiest year on file was 2022, with 15 tests reported; the quietest, 2023, had 2.
EPA's 1993 zone map puts Rhea County in Zone 3, a predicted county average under 2 pCi/L. USGS geology rates 61% of the county's land high radon potential.
Next door, the shares run from 8.7% in Cumberland County to 33.7% in Roane County, with Bledsoe County, Hamilton County and Cumberland County below Rhea County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Rhea County, Geology
The ground under Rhea County
PredictedUSGS's geologic map splits Rhea County: 61.4% of its land is high radon potential and 38.6% low. The map puts 61.4% of Rhea County in the area it calls Ridge and Valley and 38.6% in Appalachian Plateau. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Ridge and Valley | Paleozoic sandstone and cherty dolostone. | High | 14 | 61.4% |
| Appalachian Plateau | Sandstone and shale. | Low | 8 | 38.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Rhea County beside the ground around it
Rhea County has more high-potential ground than Tennessee as a whole: 61.4% of its land against 47.2%. Of the 5 counties that border it, 3 have more high-potential ground, Meigs County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Rhea County, Local resources
Radon testing and mitigation in Rhea 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
Rhea County, Questions
Questions about radon in Rhea County
Are radon levels high in Rhea County?
In 2023, 50.0% of the radon tests reported to CDC for Rhea County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.2 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 44 reported a higher share; pooled, the state comes to 33.3%.
Which counties border Rhea County?
Rhea County borders 5 counties: Meigs County, Bledsoe County, Cumberland County, Roane County and Hamilton County.
Products
Rhea County, Products
Testing a home in Rhea County
In Rhea County, 26.7% of 45 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. 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 Rhea 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
MonitorAEGTEST
HOUND-3699 radon monitor with a 2.1-inch touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
First reading: Within 1 hour
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Rhea County, Bordering counties
Counties bordering Rhea County
Calculated by Radon411- Radon levels in Meigs CountyEPA zone 1
34.5%at or above 4 pCi/L
Median 2.5 pCi/L · 29 tests · 7.8 points above Rhea County
- Radon levels in Roane CountyEPA zone 1
33.7%at or above 4 pCi/L
Median 2.5 pCi/L · 258 tests · 7.0 points above Rhea County
- Radon levels in Bledsoe CountyEPA zone 3
24.3%at or above 4 pCi/L
Median 2.1 pCi/L · 37 tests · 2.4 points below Rhea County
- Radon levels in Hamilton CountyEPA zone 2
19.3%at or above 4 pCi/L
Median 1.7 pCi/L · 1,148 tests · 7.4 points below Rhea County
- Radon levels in Cumberland CountyEPA zone 3
8.7%at or above 4 pCi/L
Median 1.3 pCi/L · 172 tests · 18.0 points below Rhea County
Rhea County, Cities and towns
Cities and towns in Rhea County
The Census Bureau estimates 34,844 residents in Rhea County for July 1, 2025, 1,542 more than in 2020 (+4.6%). That works out to 110 people per square mile of land. Its largest town, Dayton, has 7,819 residents, 22.4% of the total. Together its 3 incorporated places hold 32.5% of those residents; the other 67.5% live outside any of them. Reported testing is thin here: 45 tests over 2008 to 2017, or 1.3 for every 1,000 residents (2025 estimate), where Tennessee as a whole comes to 4.2.
From Dayton to Graysville, CDC publishes no figure by town: each reads Rhea County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Dayton | 7,819 | +5.8% | 22.4% |
| Spring City | 1,989 | +2.4% | 5.7% |
| Graysville | 1,506 | +1.8% | 4.3% |
3 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).
Rhea County, Homes
Homes in Rhea County
Of Rhea County's 15,311 homes, 68% are detached houses, against 68% across Tennessee; 20% are mobile homes. Half of its homes were built before 1991, close to Tennessee's 1986: 12% date from before 1960 and 33% from 2000 or later. 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 | Rhea County | Tennessee |
|---|---|---|
| Housing units | 15,311 | 3,095,472 |
| Detached houses | 68% | 68% |
| In buildings of 5 or more | 2% | 14% |
| Mobile homes | 20% | 8% |
| Built before 1960 | 12% | 18% |
| Built since 2000 | 33% | 29% |
| Middle year built | 1991 | 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.