Skip to content
RADON411

Locations and reports

Radon Levels in Robertson County, Tennessee

EPA puts Robertson County in Zone 2, its middle radon zone, and only 14 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    28.9%

    4.4 pts below TN

    Robertson
    28.9%
    Tennessee
    33.3%

    273 tests, 2008 to 2017

  • Median result

    1.9pCi/L

    Below action level

    Robertson
    1.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    273

    21st of 80 by tests

    Robertson
    273
    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

    41 of 80

    Middle half

    Robertson
    28.9%
    Jefferson
    56.8%

    By share, of 80 with 30+ tests

Read a result for Robertson County

Starts at Robertson County's median, 1.9 pCi/L

1.9pCi/L

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

EPA’s reading of 1.9 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Robertson County's median reported result, 2008 to 2017.

Interpret this reading

The data

Robertson County, At a glance

Robertson County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Robertson 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 97% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Robertson County, 2023

Share of reported tests at or above 4 pCi/L, by year, Robertson County
Share of reported tests at or above 4 pCi/L, by year, Robertson County
YearShare of reported tests at or above 4 pCi/L
202216.7%
20237.1%

2023: 7.1%. Across these years the share ran from 7.1% to 16.7%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 14 tests were reported to CDC for Robertson 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

Robertson County, Compared

Robertson County radon figures, compared

Calculated by Radon411

Robertson County's 273 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.9 pCi/L and a maximum of 39.3 pCi/L, and 28.9% reached 4 pCi/L. Tennessee as a whole (95 Tennessee counties, pooled) comes to 33.3%: 4.4 points higher than here.

The newest figure, in 2023, counts only 14 tests (7.1% at or above 4 pCi/L), too few to compare, so this reading uses the 273-test figure.

Among its state's counties it ranks 41st 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, 142 tests (52.0%) came in under 2 pCi/L, against 42.4% statewide, and 52 tests (19.0%) fell between 2 and 4, against 24.3% statewide. The busiest year on file was 2022, with 18 tests reported; the quietest, 2023, had 14.

EPA's 1993 zone map puts Robertson County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 97% of the county's land moderate radon potential.

Next door, the shares run from 17.7% in Todd County, KY to 36.4% in Davidson County, with Sumner County and Todd County, KY below Robertson County.

Robertson County against Tennessee, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Robertson County
Robertson County27328.9%1.9 pCi/LThis county
Tennessee, pooled95 counties, pooled31,06633.3%Not pooled+4.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+6.8 points
Jefferson Countyhighest in the state14656.8%4.7 pCi/L+27.9 points
Chester Countylowest in the state440.0%1.1 pCi/L−28.9 points
Davidson County, TNborders it5,59236.4%2.6 pCi/L+7.5 points
Cheatham County, TNborders it20534.1%2.3 pCi/L+5.2 points
Montgomery County, TNborders it59733.8%2.3 pCi/L+4.9 points
Simpson County, KYborders it12632.5%2.6 pCi/L+3.6 points
Logan County, KYborders it7931.6%2.4 pCi/L+2.7 points
Sumner County, TNborders it1,31126.0%1.9 pCi/L−2.9 points
Todd County, KYborders it6217.7%1.8 pCi/L−11.2 points
Where Robertson County's reported results fell, 2008 to 2017, laboratory, beside Tennessee and the United States
ResultRobertson County testsRobertson County shareTennessee shareU.S. shareAgainst Tennessee
Under 2 pCi/L14252.0%42.4%39.6%+9.6 points
2 to 4 pCi/L5219.0%24.3%24.7%−5.3 points
4 pCi/L and above7928.9%33.3%35.7%−4.4 points
Robertson 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
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
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
Robertson County radon tests by year, against Tennessee's pooled share
YearTestsAt or above 4 pCi/LMedianHighestTennessee, pooledChange from the row before
2023147.1%0.8 pCi/L6.8 pCi/L24.9%−9.6 points
20221816.7%2.7 pCi/L5.9 pCi/L23.8%First on file

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

Robertson County, Geology

The ground under Robertson County

Predicted

Most of the ground under Robertson County is one class on USGS's geologic map: 96.6% of its land is moderate radon potential, with 3.4% high. 96.6% of it lies in the area the map calls Highland Rim, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Robertson County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Highland RimPaleozoic sedimentary rocks (limestone, shale, chert, and dolostone).Moderate1196.6%
Cherty HighlandCherty dolostone.High123.4%

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

Robertson County beside the ground around it

Tennessee as a whole has more high-potential ground than Robertson County: 47.2% of its land, against 3.4% here. Of the 7 counties that border it, 4 have more high-potential ground, Davidson County the most at 100%.

Share of land by USGS radon potential: Robertson County, the 7 counties bordering it and Tennessee
AreaEPA zoneLow potentialModerate potentialHigh potential
Robertson CountyZone 2None96.6%3.4%
Cheatham CountyZone 2None21.0%79.0%
Davidson CountyZone 1NoneNone100%
Sumner CountyZone 2None20.4%79.6%
Simpson County, KYZone 2None100%None
Logan County, KYZone 2None100%None
Montgomery CountyZone 2None94.9%5.1%
Todd County, KYZone 2None100%None
Tennessee95 counties, pooled by land areaVaries30.5%22.3%47.2%

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

Local help

Robertson County, Local resources

Radon testing and mitigation in Robertson County

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

What it means

Robertson County, Questions

Questions about radon in Robertson County

Are radon levels high in Robertson County?

In 2023, 7.1% of the radon tests reported to CDC for Robertson County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.8 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 40 reported a higher share; pooled, the state comes to 33.3%.

Which counties border Robertson County?

Robertson County borders 7 counties: Cheatham County, TN, Davidson County, TN, Sumner County, TN, Simpson County, KY, Logan County, KY, Montgomery County, TN and Todd County, KY.

Products

Robertson County, Products

Testing a home in Robertson County

In Robertson County, 28.9% of 273 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 Robertson County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Robertson County homes, compared

Explore

Robertson County, Bordering counties

Counties bordering Robertson County

Calculated by Radon411

Robertson County, Cities and towns

Cities and towns in Robertson County

Robertson County is growing: the Census Bureau puts it at 80,175 residents on July 1, 2025, up 9.9% from 72,958 in 2020. That works out to 168 people per square mile of land. Its largest town, Springfield, has 20,090 residents, 25.1% of the total. CDC's 273 reported tests for 2008 to 2017 work out to 3.4 per 1,000 residents (2025 estimate), close to Tennessee's 4.2.

From Springfield to Cedar Hill, CDC publishes no figure by town: each reads Robertson County's.

The cities and towns in Robertson County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Springfield20,090+6.8%25.1%
White Houseextends beyond Robertson County17,872+36.6%Counted whole
Portlandextends beyond Robertson County13,658+3.5%Counted whole
Greenbrier7,170+3.1%8.9%
Millersvilleextends beyond Robertson County6,438+2.0%Counted whole
Coopertown4,843+7.9%6.0%
Ridgetopextends beyond Robertson County2,156+2.1%Counted whole
Cross Plains1,919+7.4%2.4%
Orlinda1,028+8.0%1.3%
Adams668+8.4%0.8%
Cedar Hill298−0.7%0.4%

11 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 Robertson County is counted whole, so it has no share.

Robertson County, Homes

Homes in Robertson County

Robertson County is a place of houses on their own lots: 83% of its 29,263 homes are detached single-family houses, against 68% across Tennessee. Half of its homes were built before 1993, close to Tennessee's 1986: 12% date from before 1960 and 37% 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 in Robertson County, Tennessee, 2019 to 2023
HomesRobertson CountyTennessee
Housing units29,2633,095,472
Detached houses83%68%
In buildings of 5 or more5%14%
Mobile homes8%8%
Built before 196012%18%
Built since 200037%29%
Middle year built19931986
Owner-occupied77%67%

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