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Radon Levels in Boone County, Kentucky

EPA puts Boone County in Zone 2, its middle radon zone, and high results are common there: 42.9% of the 1,434 radon tests reported to CDC (2008 to 2017, laboratory totals) 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

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  • Share at 4+ pCi/L

    42.9%

    0.8 pts below KY

    Boone
    42.9%
    Kentucky
    43.7%

    1,434 tests, 2008 to 2017

  • Median result

    3.5pCi/L

    Below action level

    Boone
    3.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    1,434

    4th of 69 by tests

    Boone
    1,434
    Jefferson
    6,590

    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 Kentucky

    27 of 69

    Middle half

    Boone
    42.9%
    Meade
    68.4%

    By share, of 69 with 30+ tests

Read a result for Boone County

Starts at Boone County's median, 3.5 pCi/L

3.5pCi/L

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

EPA’s reading of 3.5 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. Boone County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Boone County, At a glance

Boone County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Boone 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Boone County, 2008 to 2017, laboratory

Reported results by concentration band, Boone County, 2008 to 2017, laboratory
Under 2 pCi/L: 27%2 to 4 pCi/L: 30%4 pCi/L and above: 43%

Of 1,434 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Boone County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L38927.1%
2 to 4 pCi/L43030.0%
4 pCi/L and above61542.9%
What these figures count

These are the 1,434 tests reported to CDC for Boone County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Boone County, Compared

Boone County radon figures, compared

Calculated by Radon411

In Boone County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (615 of 1,434) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 7.2 points higher. Across 120 Kentucky counties pooled together, 43.7% of tests reached that level, so Boone County runs 0.8 points below its state.

Of 4 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 26.0% (Kenton County) to 34.7% (Hamilton County, OH). By share, Boone County is 27th of 69 Kentucky counties with 30 or more tests for the same period.

Half the tests came in under 3.5 pCi/L and half over it; the single highest reached 95.0 pCi/L. Below the action level, 389 tests (27.1%) came in under 2 pCi/L, against 33.2% statewide, and 430 tests (30.0%) fell between 2 and 4, against 23.1% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 42.9% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential. CDC also counts 134 tests taken after mitigation in Boone County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Boone County went from 1,196 tests (2005 to 2014) to 1,434 (2008 to 2017), the share going from 43.6% to 42.9%.

Boone County against Kentucky, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Boone County
Boone County1,43442.9%3.5 pCi/LThis county
Kentucky, pooled120 counties, pooled28,79343.7%Not pooled+0.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−7.2 points
Meade Countyhighest in the state11768.4%8.2 pCi/L+25.5 points
Hopkins Countylowest in the state429.5%1.7 pCi/L−33.4 points
Ohio County, INborders it2152.4%4.1 pCi/L+9.5 points
Hamilton County, OHborders it3,75434.7%2.8 pCi/L−8.2 points
Switzerland County, INborders it1533.3%1.5 pCi/L−9.6 points
Grant County, KYborders it7833.3%2.5 pCi/L−9.6 points
Dearborn County, INborders it13630.1%2.6 pCi/L−12.8 points
Kenton County, KYborders it1,16726.0%2.3 pCi/L−16.9 points
Gallatin County, KYborders it2425.0%2.5 pCi/L−17.9 points
Where Boone County's reported results fell, 2008 to 2017, laboratory, beside Kentucky and the United States
ResultBoone County testsBoone County shareKentucky shareU.S. shareAgainst Kentucky
Under 2 pCi/L38927.1%33.2%39.6%−6.1 points
2 to 4 pCi/L43030.0%23.1%24.7%+6.9 points
4 pCi/L and above61542.9%43.7%35.7%−0.8 points
Boone County ranked among the 69 Kentucky counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Harrison County22 of 6911146.8%3.4 pCi/L
Metcalfe County23 of 693345.5%3.5 pCi/L
Estill County24 of 6917744.1%3.2 pCi/L
Adair County25 of 695343.4%3.8 pCi/L
Franklin County26 of 6981043.1%3.3 pCi/L
Boone County27 of 691,43442.9%3.5 pCi/L
Garrard County28 of 6916439.6%2.6 pCi/L
Jefferson County29 of 696,59039.4%2.7 pCi/L
Madison County30 of 6960438.7%2.9 pCi/L
Mercer County31 of 6928838.2%2.7 pCi/L
Shelby County32 of 6940737.6%3.0 pCi/L
Boone County ten-year laboratory totals, against Kentucky's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestKentucky, pooledChange from the row before
2008 to 20171,43442.9%3.5 pCi/L95.0 pCi/L43.7%+0.5 points
2007 to 20161,45942.4%3.4 pCi/L95.0 pCi/L45.1%−1.5 points
2006 to 20151,32043.9%3.5 pCi/L95.0 pCi/L46.4%+0.3 points
2005 to 20141,19643.6%3.5 pCi/L95.0 pCi/L47.3%First on file

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

Boone County, Geology

The ground under Boone County

Predicted

USGS's geologic map puts all of Boone County's mapped land in one class: moderate radon potential. 98.7% of it lies in the area the map calls Outer Bluegrass, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Boone County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Outer BluegrassOrdovician-Devonian limestone and shale.Moderate1198.7%
Dearborn UplandOrdovician through Devonian limestone, dolostone, and gray shale, and pre-Wisconsinan glacial deposits.Moderate100.9%

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

Boone County beside the ground around it

Across Kentucky 18.2% of the land is rated high; none of Boone County's is. Of the 7 counties that border it, 2 have more high-potential ground, Kenton County the most at 18.7%.

Share of land by USGS radon potential: Boone County, the 7 counties bordering it and Kentucky
AreaEPA zoneLow potentialModerate potentialHigh potential
Boone CountyZone 2None100%None
Kenton CountyZone 2None81.3%18.7%
Ohio County, INZone 2None100%None
Gallatin CountyZone 2None100%None
Hamilton County, OHZone 1None88.5%11.5%
Switzerland County, INZone 2None100%None
Dearborn County, INZone 2None100%None
Grant CountyZone 2None100%None
Kentucky120 counties, pooled by land areaVaries5.7%76.1%18.2%

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

Local help

Boone County, Local resources

Radon testing and mitigation in Boone County

Listed radon businesses with an address in Boone County:

Listed radon professionals by town: Florence, Union

What Kentucky's program says
Phone
502-782-2782
Email
Radon@ky.gov

What it means

Boone County, Questions

Questions about radon in Boone County

Are radon levels high in Boone County?

Over the 2008 to 2017 laboratory totals, 42.9% of the radon tests reported to CDC for Boone County, Kentucky were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of 69 Kentucky counties with 30 or more tests for the same period, 26 reported a higher share; pooled, the state comes to 43.7%.

Which counties border Boone County?

Boone County borders 7 counties: Kenton County, KY, Ohio County, IN, Gallatin County, KY, Hamilton County, OH, Switzerland County, IN, Dearborn County, IN and Grant County, KY.

Products

Boone County, Products

Testing a home in Boone County

In Boone County, 42.9% of 1,434 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 43.7% pooled across Kentucky. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Boone County; a long-term test tells the year-round average.

Test kits and monitors3

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Best radon monitors for Boone County homes, compared

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Boone County, Bordering counties

Counties bordering Boone County

Calculated by Radon411

Boone County, Cities and towns

Cities and towns in Boone County

Boone County is growing: the Census Bureau puts it at 145,316 residents on July 1, 2025, up 6.5% from 136,472 in 2020. That works out to 590 people per square mile of land. Its largest town, Florence, has 34,018 residents, 23.4% of the total. Testing is reported here more often than across the state: CDC's 1,434 reported tests for 2008 to 2017 come to 9.9 for every 1,000 residents (2025 estimate), against 6.3 for Kentucky.

From Florence to Walton, CDC publishes no figure by town: each reads Boone County's.

The cities and towns in Boone County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Florence34,018+6.0%23.4%
Erlangerextends beyond Boone County20,158+2.4%Counted whole
Union7,937+6.5%5.5%
Waltonextends beyond Boone County5,868+6.6%Counted whole

4 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 Boone County is counted whole, so it has no share.

Boone County, Homes

Homes in Boone County

Of Boone County's 52,476 homes, 69% are detached houses, against 68% across Kentucky; 18% are in buildings of five or more homes. Much of Boone County is recent building: 40% of its homes have gone up since 2000 and the middle year built is 1995, against 1982 for Kentucky. Owners live in 77% of the occupied homes (Kentucky: 68%), so for most households a test and a fix are their own to order.

Homes in Boone County, Kentucky, 2019 to 2023
HomesBoone CountyKentucky
Housing units52,4762,010,655
Detached houses69%68%
In buildings of 5 or more18%12%
Mobile homes4%11%
Built before 19608%22%
Built since 200040%24%
Middle year built19951982
Owner-occupied77%68%

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