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Radon Levels in Stewart County, Tennessee

EPA puts Stewart County in Zone 2, its middle radon zone, and only 1 radon test from it is 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

    26.3%

    7.0 pts below TN

    Stewart
    26.3%
    Tennessee
    33.3%

    95 tests, 2008 to 2017

  • Median result

    2.1pCi/L

    Below action level

    Stewart
    2.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    95

    47th of 80 by tests

    Stewart
    95
    Davidson
    5,592

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Tennessee

    46 of 80

    Middle half

    Stewart
    26.3%
    Jefferson
    56.8%

    By share, of 80 with 30+ tests

Read a result for Stewart County

Starts at Stewart County's median, 2.1 pCi/L

2.1pCi/L

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

EPA’s reading of 2.1 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. Stewart County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Stewart County, At a glance

Stewart County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Stewart County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 83% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Stewart County, 2023

CDC holds 1 reported test for Stewart County in 2023, a result of 2.7 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Stewart County beside the counties around it is how this page reads it.

What these figures count

Only 1 test was reported to CDC for Stewart 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

Stewart County, Compared

Stewart County radon figures, compared

Calculated by Radon411

Stewart County's 95 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.1 pCi/L and a maximum of 17.3 pCi/L, and 26.3% reached 4 pCi/L. Tennessee as a whole (95 Tennessee counties, pooled) comes to 33.3%: 7.0 points higher than here.

The newest figure, in 2023, counts only 1 test (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 95-test figure.

Among its state's counties it ranks 46th 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, 46 tests (48.4%) came in under 2 pCi/L, against 42.4% statewide, and 24 tests (25.3%) fell between 2 and 4, against 24.3% statewide. CDC's ten-year totals for Stewart County went from 83 tests (2005 to 2014) to 95 (2008 to 2017), the share going from 24.1% to 26.3%.

EPA's 1993 zone map puts Stewart County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 83% of the county's land moderate radon potential.

Next door, the shares run from 16.7% in Henry County to 36.1% in Christian County, KY, with Trigg County, KY and Henry County below Stewart County.

CDC also counts 7 tests taken after mitigation in Stewart County for the same period: tests in homes where a fix was already in.

Stewart County against Tennessee, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Stewart County
Stewart County9526.3%2.1 pCi/LThis county
Tennessee, pooled95 counties, pooled31,06633.3%Not pooled+7.0 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+9.4 points
Jefferson Countyhighest in the state14656.8%4.7 pCi/L+30.5 points
Chester Countylowest in the state440.0%1.1 pCi/L−26.3 points
Christian County, KYborders it7236.1%3.2 pCi/L+9.8 points
Montgomery County, TNborders it59733.8%2.3 pCi/L+7.5 points
Benton County, TNborders it3033.3%2.0 pCi/L+7.0 points
Houston County, TNborders it1428.6%2.8 pCi/L+2.3 points
Trigg County, KYborders it4522.2%2.4 pCi/L−4.1 points
Calloway County, KYborders it2722.2%2.4 pCi/L−4.1 points
Henry County, TNborders it6016.7%1.6 pCi/L−9.6 points
Where Stewart County's reported results fell, 2008 to 2017, laboratory, beside Tennessee and the United States
ResultStewart County testsStewart County shareTennessee shareU.S. shareAgainst Tennessee
Under 2 pCi/L4648.4%42.4%39.6%+6.0 points
2 to 4 pCi/L2425.3%24.3%24.7%+1.0 points
4 pCi/L and above2526.3%33.3%35.7%−7.0 points
Stewart 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
Marion County42 of 807428.4%1.6 pCi/L
Polk County43 of 804327.9%2.2 pCi/L
Trousdale County44 of 803327.3%1.8 pCi/L
Rhea County45 of 804526.7%2.4 pCi/L
Dickson County46 of 8020926.3%2.1 pCi/L
Stewart County46 of 809526.3%2.1 pCi/L
Sumner County48 of 801,31126.0%1.9 pCi/L
Williamson County49 of 803,41425.8%2.0 pCi/L
Franklin County50 of 8026625.6%2.1 pCi/L
Bledsoe County51 of 803724.3%2.1 pCi/L
Humphreys County52 of 8010523.8%2.0 pCi/L
Stewart County ten-year laboratory totals, against Tennessee's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestTennessee, pooledChange from the row before
2008 to 20179526.3%2.1 pCi/L17.3 pCi/L33.3%+1.3 points
2007 to 20169225.0%2.1 pCi/L17.3 pCi/L33.4%−1.2 points
2006 to 20158426.2%2.1 pCi/L17.3 pCi/L33.4%+2.1 points
2005 to 20148324.1%2.1 pCi/L15.3 pCi/L33.2%First on file

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

Stewart County, Geology

The ground under Stewart County

Predicted

Most of the ground under Stewart County is one class on USGS's geologic map: 82.7% of its land is moderate radon potential, with 17.3% high. The map puts 82.7% of Stewart County in the area it calls Highland Rim and 17.3% in Cherty Highland. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Stewart County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Highland RimPaleozoic sedimentary rocks (limestone, shale, chert, and dolostone).Moderate1182.7%
Cherty HighlandCherty dolostone.High1217.3%

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

Stewart County beside the ground around it

Tennessee as a whole has more high-potential ground than Stewart County: 47.2% of its land, against 17.3% here. Of the 7 counties that border it, 2 have more high-potential ground, Benton County the most at 65.8%.

Share of land by USGS radon potential: Stewart County, the 7 counties bordering it and Tennessee
AreaEPA zoneLow potentialModerate potentialHigh potential
Stewart CountyZone 2None82.7%17.3%
Houston CountyZone 2None78.5%21.5%
Trigg County, KYZone 2None100%None
Calloway County, KYZone 378.2%19.6%2.2%
Montgomery CountyZone 2None94.9%5.1%
Henry CountyZone 361.5%30.4%8.1%
Christian County, KYZone 2None100%None
Benton CountyZone 2None34.2%65.8%
Tennessee95 counties, pooled by land areaVaries30.5%22.3%47.2%

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

Local help

Stewart County, Local resources

Radon testing and mitigation in Stewart County

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

What it means

Stewart County, Questions

Questions about radon in Stewart County

Are radon levels high in Stewart County?

In 2023, 0.0% of the radon tests reported to CDC for Stewart County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.7 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 45 reported a higher share; pooled, the state comes to 33.3%.

Which counties border Stewart County?

Stewart County borders 7 counties: Houston County, TN, Trigg County, KY, Calloway County, KY, Montgomery County, TN, Henry County, TN, Christian County, KY and Benton County, TN.

Products

Stewart County, Products

Testing a home in Stewart County

In Stewart County, 26.3% of 95 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 Stewart County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Stewart County homes, compared

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Stewart County, Bordering counties

Counties bordering Stewart County

Calculated by Radon411

Stewart County, Cities and towns

Cities and towns in Stewart County

Stewart County is growing: the Census Bureau puts it at 14,439 residents on July 1, 2025, up 5.3% from 13,708 in 2020. That works out to 31 people per square mile of land. No town dominates: Dover, the largest, has 1,918 residents, 13.3% of the total. Together its 2 incorporated places hold 15.6% of those residents; the other 84.4% live outside any of them. Testing is reported here more often than across the state: CDC's 95 reported tests for 2008 to 2017 come to 6.6 for every 1,000 residents (2025 estimate), against 4.2 for Tennessee.

From Dover to Cumberland City, CDC publishes no figure by town: each reads Stewart County's.

The cities and towns in Stewart County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Dover1,918+4.4%13.3%
Cumberland City330+7.5%2.3%

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).

Stewart County, Homes

Homes in Stewart County

Of Stewart County's 6,698 homes, 75% are detached houses, against 68% across Tennessee; 21% are mobile homes. Half of its homes were built before 1989, close to Tennessee's 1986: 13% date from before 1960 and 27% from 2000 or later. Owners live in 84% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.

Homes in Stewart County, Tennessee, 2019 to 2023
HomesStewart CountyTennessee
Housing units6,6983,095,472
Detached houses75%68%
In buildings of 5 or more2%14%
Mobile homes21%8%
Built before 196013%18%
Built since 200027%29%
Middle year built19891986
Owner-occupied84%67%

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