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Radon Levels in Bullitt County, Kentucky

EPA puts Bullitt County in Zone 1, its highest radon zone, and high results are common there: 47.5% of the 551 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

    47.5%

    3.8 pts above KY

    Bullitt
    47.5%
    Kentucky
    43.7%

    551 tests, 2008 to 2017

  • Median result

    3.6pCi/L

    Below action level

    Bullitt
    3.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    551

    11th of 69 by tests

    Bullitt
    551
    Jefferson
    6,590

    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 Kentucky

    18 of 69

    Middle half

    Bullitt
    47.5%
    Meade
    68.4%

    By share, of 69 with 30+ tests

Read a result for Bullitt County

Starts at Bullitt County's median, 3.6 pCi/L

3.6pCi/L

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

EPA’s reading of 3.6 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. Bullitt County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Bullitt County, At a glance

Bullitt County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Bullitt 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 73% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Bullitt County, 2008 to 2017, laboratory
Under 2 pCi/L: 32%2 to 4 pCi/L: 20%4 pCi/L and above: 48%

Of 551 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Bullitt County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L17832.3%
2 to 4 pCi/L11120.1%
4 pCi/L and above26247.5%
What these figures count

These are the 551 tests reported to CDC for Bullitt 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

Bullitt County, Compared

Bullitt County radon figures, compared

Calculated by Radon411

In Bullitt County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (262 of 551) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 11.8 points higher. Across 120 Kentucky counties pooled together, 43.7% of tests reached that level, so Bullitt County runs 3.8 points above its state.

Of 4 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 31.3% (Spencer County) to 66.1% (Nelson County). By share, Bullitt County is 18th of 69 Kentucky counties with 30 or more tests for the same period.

Half the tests came in under 3.6 pCi/L and half over it; the single highest reached 99.0 pCi/L. Below the action level, 178 tests (32.3%) came in under 2 pCi/L, against 33.2% statewide, and 111 tests (20.1%) fell between 2 and 4, against 23.1% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 47.5% share point the same way here. USGS geology rates 73% of the county's land high radon potential. CDC also counts 27 tests taken after mitigation in Bullitt County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Bullitt County went from 363 tests (2005 to 2014) to 551 (2008 to 2017), the share going from 55.6% to 47.5%.

Bullitt County against Kentucky, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Bullitt County
Bullitt County55147.5%3.6 pCi/LThis county
Kentucky, pooled120 counties, pooled28,79343.7%Not pooled−3.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−11.8 points
Meade Countyhighest in the state11768.4%8.2 pCi/L+20.9 points
Hopkins Countylowest in the state429.5%1.7 pCi/L−38.0 points
Nelson County, KYborders it30466.1%6.3 pCi/L+18.6 points
Hardin County, KYborders it42950.3%4.0 pCi/L+2.8 points
Jefferson County, KYborders it6,59039.4%2.7 pCi/L−8.1 points
Spencer County, KYborders it16631.3%2.5 pCi/L−16.2 points
Where Bullitt County's reported results fell, 2008 to 2017, laboratory, beside Kentucky and the United States
ResultBullitt County testsBullitt County shareKentucky shareU.S. shareAgainst Kentucky
Under 2 pCi/L17832.3%33.2%39.6%−0.9 points
2 to 4 pCi/L11120.1%23.1%24.7%−3.0 points
4 pCi/L and above26247.5%43.7%35.7%+3.8 points
Bullitt 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
Monroe County13 of 698752.9%4.6 pCi/L
Barren County14 of 6918651.6%4.0 pCi/L
Montgomery County15 of 6910551.4%4.1 pCi/L
Hardin County16 of 6942950.3%4.0 pCi/L
Marion County17 of 6917748.6%3.9 pCi/L
Bullitt County18 of 6955147.5%3.6 pCi/L
Clinton County19 of 694047.5%3.5 pCi/L
Larue County20 of 693447.1%3.7 pCi/L
Scott County21 of 6987546.9%3.6 pCi/L
Harrison County22 of 6911146.8%3.4 pCi/L
Metcalfe County23 of 693345.5%3.5 pCi/L
Bullitt County ten-year laboratory totals, against Kentucky's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestKentucky, pooledChange from the row before
2008 to 201755147.5%3.6 pCi/L99.0 pCi/L43.7%−3.6 points
2007 to 201647951.1%4.1 pCi/L99.0 pCi/L45.1%−2.7 points
2006 to 201540753.8%4.6 pCi/L167.6 pCi/L46.4%−1.8 points
2005 to 201436355.6%4.9 pCi/L167.6 pCi/L47.3%First on file

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

Bullitt County, Geology

The ground under Bullitt County

Predicted

USGS's geologic map splits Bullitt County: 73.4% of its land is high radon potential and 26.6% moderate. The map puts 73.4% of Bullitt County in the area it calls New Albany-Chattanooga Shale and 17.9% in Mississippian Plateau, with one smaller area beside them. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Bullitt County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
New Albany-Chattanooga ShaleDevonian/Mississippian Black shale.High1473.4%
Mississippian PlateauMississippian marine limestones, dolomites, marine sandstones, siltstones, and shales.Moderate1117.9%
Outer BluegrassOrdovician-Devonian limestone and shale.Moderate118.7%

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

Bullitt County beside the ground around it

Bullitt County has more high-potential ground than Kentucky as a whole: 73.4% of its land against 18.2%. Of the 4 counties that border it, none has as large a share of high-potential ground; Jefferson County comes nearest at 55.1%.

Share of land by USGS radon potential: Bullitt County, the 4 counties bordering it and Kentucky
AreaEPA zoneLow potentialModerate potentialHigh potential
Bullitt CountyZone 1None26.6%73.4%
Jefferson CountyZone 1None44.9%55.1%
Nelson CountyZone 1None45.9%54.1%
Hardin CountyZone 2None96.6%3.4%
Spencer 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

Bullitt County, Local resources

Radon testing and mitigation in Bullitt County

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

What it means

Bullitt County, Questions

Questions about radon in Bullitt County

Are radon levels high in Bullitt County?

Over the 2008 to 2017 laboratory totals, 47.5% of the radon tests reported to CDC for Bullitt County, Kentucky were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.6 pCi/L. Of 69 Kentucky counties with 30 or more tests for the same period, 17 reported a higher share; pooled, the state comes to 43.7%.

Which counties border Bullitt County?

Bullitt County borders 4 counties: Jefferson County, Nelson County, Hardin County and Spencer County.

Products

Bullitt County, Products

Testing a home in Bullitt County

In Bullitt County, 47.5% of 551 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 43.7% pooled across Kentucky. In Zone 1 the year-round level in Bullitt 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

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

Explore

Bullitt County, Bordering counties

Counties bordering Bullitt County

Calculated by Radon411

Bullitt County, Cities and towns

Cities and towns in Bullitt County

The Census Bureau estimates 86,454 residents in Bullitt County for July 1, 2025, 4,089 more than in 2020 (+5.0%). That works out to 291 people per square mile of land. Its largest town, Mount Washington, has 18,989 residents, 22.0% of the total. Together its 8 incorporated places hold 57.2% of those residents; the other 42.8% live outside any of them. CDC's 551 reported tests for 2008 to 2017 work out to 6.4 per 1,000 residents (2025 estimate), close to Kentucky's 6.3.

From Mount Washington to Hunters Hollow, CDC publishes no figure by town: each reads Bullitt County's.

The cities and towns in Bullitt County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Mount Washington18,989+4.8%22.0%
Shepherdsville14,931+5.0%17.3%
Hillview9,020+4.3%10.4%
Pioneer Village2,794+4.5%3.2%
Lebanon Junction1,837+4.7%2.1%
Hebron Estates1,056+4.3%1.2%
Fox Chase458+4.6%0.5%
Hunters Hollow338+4.6%0.4%

8 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).

Bullitt County, Homes

Homes in Bullitt County

Bullitt County is a place of houses on their own lots: 80% of its 33,222 homes are detached single-family houses, against 68% across Kentucky. Much of Bullitt County is recent building: 33% of its homes have gone up since 2000 and the middle year built is 1992, against 1982 for Kentucky. Owners live in 84% of the occupied homes (Kentucky: 68%), so for most households a test and a fix are their own to order.

Homes in Bullitt County, Kentucky, 2019 to 2023
HomesBullitt CountyKentucky
Housing units33,2222,010,655
Detached houses80%68%
In buildings of 5 or more5%12%
Mobile homes7%11%
Built before 19607%22%
Built since 200033%24%
Middle year built19921982
Owner-occupied84%68%

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