Skip to content
RADON411

Locations and reports

Radon Levels in Gibson County, Indiana

EPA puts Gibson County in Zone 2, its middle radon zone, and high results are common there: 43.3% of the 120 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    43.3%

    4.4 pts above IN

    Gibson
    43.3%
    Indiana
    38.9%

    120 tests, 2008 to 2017

  • Median result

    3.4pCi/L

    Below action level

    Gibson
    3.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    120

    40th of 69 by tests

    Gibson
    120
    St. Joseph
    7,346

    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 Indiana

    34 of 69

    Middle half

    Gibson
    43.3%
    Miami
    63.3%

    By share, of 69 with 30+ tests

Read a result for Gibson County

Starts at Gibson County's median, 3.4 pCi/L

3.4pCi/L

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

EPA’s reading of 3.4 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. Gibson County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Gibson County, At a glance

Gibson County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Gibson 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 Gibson County, 2008 to 2017, laboratory

Reported results by concentration band, Gibson County, 2008 to 2017, laboratory
Under 2 pCi/L: 26%2 to 4 pCi/L: 31%4 pCi/L and above: 43%

Of 120 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Gibson County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L3125.8%
2 to 4 pCi/L3730.8%
4 pCi/L and above5243.3%
What these figures count

These are the 120 tests reported to CDC for Gibson 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

Gibson County, Compared

Gibson County radon figures, compared

Calculated by Radon411

In Gibson County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (52 of 120) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 7.6 points higher. Across 92 Indiana counties pooled together, 38.9% of tests reached that level, so Gibson County runs 4.4 points above its state.

Of 6 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 20.9% (Warrick County) to 43.1% (Knox County). By share, Gibson County is 34th of 69 Indiana counties with 30 or more tests for the same period.

Half the tests came in under 3.4 pCi/L and half over it; the single highest reached 24.6 pCi/L. Below the action level, 31 tests (25.8%) came in under 2 pCi/L, against 32.8% statewide, and 37 tests (30.8%) fell between 2 and 4, against 28.3% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 43.3% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential. CDC also counts 7 tests taken after mitigation in Gibson County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Gibson County went from 82 tests (2005 to 2014) to 120 (2008 to 2017), the share going from 37.8% to 43.3%.

Gibson County against Indiana, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Gibson County
Gibson County12043.3%3.4 pCi/LThis county
Indiana, pooled92 counties, pooled43,14838.9%Not pooled−4.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−7.6 points
Miami Countyhighest in the state3063.3%5.3 pCi/L+20.0 points
Jasper Countylowest in the state7114.1%1.2 pCi/L−29.2 points
Pike County, INborders it650.0%3.6 pCi/L+6.7 points
Knox County, INborders it5843.1%3.4 pCi/L−0.2 points
Posey County, INborders it21535.3%2.8 pCi/L−8.0 points
Wabash County, ILborders it3432.4%3.0 pCi/L−10.9 points
White County, ILborders it3429.4%2.9 pCi/L−13.9 points
Vanderburgh County, INborders it1,50524.4%2.4 pCi/L−18.9 points
Warrick County, INborders it56120.9%1.8 pCi/L−22.4 points
Where Gibson County's reported results fell, 2008 to 2017, laboratory, beside Indiana and the United States
ResultGibson County testsGibson County shareIndiana shareU.S. shareAgainst Indiana
Under 2 pCi/L3125.8%32.8%39.6%−7.0 points
2 to 4 pCi/L3730.8%28.3%24.7%+2.5 points
4 pCi/L and above5243.3%38.9%35.7%+4.4 points
Gibson County ranked among the 69 Indiana counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Jefferson County29 of 697245.8%3.1 pCi/L
Morgan County30 of 6922644.2%3.5 pCi/L
Dubois County31 of 6913644.1%3.7 pCi/L
Vigo County32 of 6945544.0%3.6 pCi/L
Huntington County33 of 6916943.8%3.5 pCi/L
Gibson County34 of 6912043.3%3.4 pCi/L
Knox County35 of 695843.1%3.4 pCi/L
Floyd County36 of 6931642.4%3.3 pCi/L
Washington County37 of 693842.1%3.5 pCi/L
Allen County38 of 693,99041.8%3.3 pCi/L
LaGrange County39 of 6912041.7%3.4 pCi/L
Gibson County ten-year laboratory totals, against Indiana's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIndiana, pooledChange from the row before
2008 to 201712043.3%3.4 pCi/L24.6 pCi/L38.9%+1.6 points
2007 to 201610841.7%3.4 pCi/L24.6 pCi/L39.2%+3.0 points
2006 to 20159338.7%3.2 pCi/L24.6 pCi/L39.6%+0.9 points
2005 to 20148237.8%3.1 pCi/L24.6 pCi/L39.3%First on file

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

Gibson County, Geology

The ground under Gibson County

Predicted

USGS's geologic map puts all of Gibson County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Wabash Lowland, to which USGS gives a radon index of 10, in the moderate band (9 to 11).

USGS's geologic areas under Gibson County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Wabash LowlandLoess, pre-Wisconsinan glacial deposits, Pennsylvanian shale, sandstone, and carbonate bedrock.Moderate1099.9%

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

Gibson County beside the ground around it

Across Indiana 56.6% of the land is rated high; none of Gibson County's is. Of the 7 counties that border it, none has as large a share of moderate-potential ground; Knox County comes nearest at 100%.

Share of land by USGS radon potential: Gibson County, the 7 counties bordering it and Indiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Gibson CountyZone 2None100%None
Wabash County, ILZone 2None100%None
Pike CountyZone 2None100%None
Vanderburgh CountyZone 2None100%None
Knox CountyZone 2None100%None
Warrick CountyZone 2None100%None
Posey CountyZone 2None100%None
White County, ILZone 2None100%None
Indiana92 counties, pooled by land areaVariesNone43.4%56.6%

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

Local help

Gibson County, Local resources

Radon testing and mitigation in Gibson County

What Indiana's program says
Phone
1-800-272-9723
Licensing of radon professionals
According to the Indiana Radon Rule, 410 IAC 5.1, everyone who is serving Indiana by doing radon testing, analysis and mitigation (radon reduction) in residential structures must be certified by the Indiana State Department of Health.

What it means

Gibson County, Questions

Questions about radon in Gibson County

Are radon levels high in Gibson County?

Over the 2008 to 2017 laboratory totals, 43.3% of the radon tests reported to CDC for Gibson County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.4 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 33 reported a higher share; pooled, the state comes to 38.9%.

Which counties border Gibson County?

Gibson County borders 7 counties: Wabash County, IL, Pike County, IN, Vanderburgh County, IN, Knox County, IN, Warrick County, IN, Posey County, IN and White County, IL.

Products

Gibson County, Products

Testing a home in Gibson County

In Gibson County, 43.3% of 120 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 38.9% pooled across Indiana. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Gibson County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Gibson County homes, compared

Explore

Gibson County, Bordering counties

Counties bordering Gibson County

Calculated by Radon411

Gibson County, Cities and towns

Cities and towns in Gibson County

Gibson County's population has barely moved since 2020: 33,091 residents on July 1, 2025 against 33,059 then, by the Census Bureau's estimates. That works out to 68 people per square mile of land. Its largest town, Princeton, has 8,524 residents, 25.8% of the total. Together its 10 incorporated places hold 55.9% of those residents; the other 44.1% live outside any of them. Reported testing is thin here: 120 tests over 2008 to 2017, or 3.6 for every 1,000 residents (2025 estimate), where Indiana as a whole comes to 6.2.

From Princeton to Mackey, CDC publishes no figure by town: each reads Gibson County's.

The cities and towns in Gibson County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Princeton8,524+2.5%25.8%
Fort Branch2,936−1.1%8.9%
Oakland City2,274−0.7%6.9%
Haubstadt1,610−1.8%4.9%
Owensville1,332Level4.0%
Patoka706+0.1%2.1%
Francisco539−0.6%1.6%
Somerville249Level0.8%
Hazleton196−1.0%0.6%
Mackey127−2.3%0.4%

10 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).

Gibson County, Homes

Homes in Gibson County

Gibson County is a place of houses on their own lots: 78% of its 14,762 homes are detached single-family houses, against 73% across Indiana. Half of its homes were built before 1973, close to Indiana's 1976: 38% date from before 1960 and 19% from 2000 or later. Owners live in 76% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.

Homes in Gibson County, Indiana, 2019 to 2023
HomesGibson CountyIndiana
Housing units14,7622,953,344
Detached houses78%73%
In buildings of 5 or more6%13%
Mobile homes9%4%
Built before 196038%32%
Built since 200019%21%
Middle year built19731976
Owner-occupied76%70%

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