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Radon Levels in Roane County, Tennessee

EPA puts Roane County in Zone 1, its highest radon zone, and only 20 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

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  • Share at 4+ pCi/L

    33.7%

    0.4 pts above TN

    Roane
    33.7%
    Tennessee
    33.3%

    258 tests, 2008 to 2017

  • Median result

    2.5pCi/L

    Below action level

    Roane
    2.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    258

    24th of 80 by tests

    Roane
    258
    Davidson
    5,592

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Tennessee

    36 of 80

    Middle half

    Roane
    33.7%
    Jefferson
    56.8%

    By share, of 80 with 30+ tests

Read a result for Roane County

Starts at Roane County's median, 2.5 pCi/L

2.5pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 2.5 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 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. Roane County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Roane County, At a glance

Roane County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Roane County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 97% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Roane County, 2023

Share of reported tests at or above 4 pCi/L, by year, Roane County
Share of reported tests at or above 4 pCi/L, by year, Roane County
YearShare of reported tests at or above 4 pCi/L
202217.1%
202320.0%

2023: 20.0%. Across these years the share ran from 17.1% to 20.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 20 tests were reported to CDC for Roane 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).

How to read these figures

Roane County, Compared

Roane County radon figures, compared

Calculated by Radon411

In Roane County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (87 of 258) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 2.0 points lower. Across 95 Tennessee counties pooled together, 33.3% of tests reached that level, so Roane County runs 0.4 points above its state.

The newest figure, in 2023, counts only 20 tests (20.0% at or above 4 pCi/L), too few to compare, so this reading uses the 258-test figure.

Of 7 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 6.5% (Morgan County) to 54.5% (Loudon County). By share, Roane County is 36th of 80 Tennessee counties with 30 or more tests for the same period.

Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 159.3 pCi/L. Below the action level, 101 tests (39.1%) came in under 2 pCi/L, against 42.4% statewide, and 70 tests (27.1%) fell between 2 and 4, against 24.3% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 33.7% share point the same way here. USGS geology rates 97% of the county's land high radon potential. CDC also counts 11 tests taken after mitigation in Roane County for the same period: tests in homes where a fix was already in.

The busiest year on file was 2022, with 105 tests reported; the quietest, 2023, had 20.

Roane County against Tennessee, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Roane County
Roane County25833.7%2.5 pCi/LThis county
Tennessee, pooled95 counties, pooled31,06633.3%Not pooled−0.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+2.0 points
Jefferson Countyhighest in the state14656.8%4.7 pCi/L+23.1 points
Chester Countylowest in the state440.0%1.1 pCi/L−33.7 points
Loudon County, TNborders it85954.5%4.4 pCi/L+20.8 points
Anderson County, TNborders it26948.3%3.8 pCi/L+14.6 points
Meigs County, TNborders it2934.5%2.5 pCi/L+0.8 points
McMinn County, TNborders it10634.0%2.8 pCi/L+0.3 points
Knox County, TNborders it2,45233.6%2.5 pCi/L−0.1 points
Rhea County, TNborders it4526.7%2.4 pCi/L−7.0 points
Cumberland County, TNborders it1728.7%1.3 pCi/L−25.0 points
Morgan County, TNborders it316.5%1.7 pCi/L−27.2 points
Where Roane County's reported results fell, 2008 to 2017, laboratory, beside Tennessee and the United States
ResultRoane County testsRoane County shareTennessee shareU.S. shareAgainst Tennessee
Under 2 pCi/L10139.1%42.4%39.6%−3.3 points
2 to 4 pCi/L7027.1%24.3%24.7%+2.8 points
4 pCi/L and above8733.7%33.3%35.7%+0.4 points
Roane County ranked among the 80 Tennessee counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Clay County31 of 804634.8%2.3 pCi/L
Johnson County32 of 8015734.4%2.3 pCi/L
Cheatham County33 of 8020534.1%2.3 pCi/L
McMinn County34 of 8010634.0%2.8 pCi/L
Montgomery County35 of 8059733.8%2.3 pCi/L
Roane County36 of 8025833.7%2.5 pCi/L
Knox County37 of 802,45233.6%2.5 pCi/L
Benton County38 of 803033.3%2.0 pCi/L
Perry County39 of 804032.5%2.0 pCi/L
DeKalb County40 of 805930.5%3.1 pCi/L
Robertson County41 of 8027328.9%1.9 pCi/L
Roane County radon tests by year, against Tennessee's pooled share
YearTestsAt or above 4 pCi/LMedianHighestTennessee, pooledChange from the row before
20232020.0%2.2 pCi/L8.4 pCi/L24.9%+2.9 points
202210517.1%1.6 pCi/L10.7 pCi/L23.8%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Roane County, Geology

The ground under Roane County

Predicted

Most of the ground under Roane County is one class on USGS's geologic map: 97.3% of its land is high radon potential, with 2.7% low. 97.3% 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).

USGS's geologic areas under Roane County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Ridge and ValleyPaleozoic sandstone and cherty dolostone.High1497.3%
Appalachian PlateauSandstone and shale.Low82.7%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Roane County beside the ground around it

Roane County has more high-potential ground than Tennessee as a whole: 97.3% of its land against 47.2%. Of the 8 counties that border it, 4 have more high-potential ground, Knox County the most at 100%.

Share of land by USGS radon potential: Roane County, the 8 counties bordering it and Tennessee
AreaEPA zoneLow potentialModerate potentialHigh potential
Roane CountyZone 12.7%None97.3%
Loudon CountyZone 1NoneNone100%
Morgan CountyZone 398.7%None1.3%
Cumberland CountyZone 3100%NoneNone
Anderson CountyZone 131.4%None68.6%
Rhea CountyZone 338.6%None61.4%
Meigs CountyZone 1NoneNone100%
McMinn CountyZone 1NoneNone100%
Knox CountyZone 1NoneNone100%
Tennessee95 counties, pooled by land areaVaries30.5%22.3%47.2%

The map rates the ground, not the air in any home.

Local help

Roane County, Local resources

Radon testing and mitigation in Roane County

What Tennessee's program says
Phone
1-800-232-1139
Email
TDEC.Radon@tn.gov

What it means

Roane County, Questions

Questions about radon in Roane County

Are radon levels high in Roane County?

In 2023, 20.0% of the radon tests reported to CDC for Roane County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.2 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 35 reported a higher share; pooled, the state comes to 33.3%.

Which counties border Roane County?

Roane County borders 8 counties: Loudon County, Morgan County, Cumberland County, Anderson County, Rhea County, Meigs County, McMinn County and Knox County.

Products

Roane County, Products

Testing a home in Roane County

In Roane County, 33.7% of 258 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. In Zone 1 the year-round level in Roane 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

Roane County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Roane County

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Roane County, Bordering counties

Counties bordering Roane County

Calculated by Radon411

Roane County, Cities and towns

Cities and towns in Roane County

Roane County is growing: the Census Bureau puts it at 57,395 residents on July 1, 2025, up 6.9% from 53,666 in 2020. That works out to 159 people per square mile of land. Oak Ridge, the largest place on its list (35,395 residents in all), extends beyond Roane County, so no share of the total is worked out for it. CDC's 258 reported tests for 2008 to 2017 work out to 4.5 per 1,000 residents (2025 estimate), close to Tennessee's 4.2.

From Oak Ridge to Oliver Springs, CDC publishes no figure by town: each reads Roane County's.

The cities and towns in Roane County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Oak Ridgeextends beyond Roane County35,395+11.6%Counted whole
Kingston6,299+3.7%11.0%
Harrimanextends beyond Roane County6,192+4.4%Counted whole
Rockwood5,607+3.2%9.8%
Oliver Springsextends beyond Roane County3,433+4.4%Counted whole

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 Roane County is counted whole, so it has no share.

Roane County, Homes

Homes in Roane County

Roane County is a place of houses on their own lots: 76% of its 25,560 homes are detached single-family houses, against 68% across Tennessee. Half of its homes were built before 1979, close to Tennessee's 1986: 23% date from before 1960 and 22% from 2000 or later. Owners live in 78% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.

Homes in Roane County, Tennessee, 2019 to 2023
HomesRoane CountyTennessee
Housing units25,5603,095,472
Detached houses76%68%
In buildings of 5 or more5%14%
Mobile homes13%8%
Built before 196023%18%
Built since 200022%29%
Middle year built19791986
Owner-occupied78%67%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.