Skip to content
RADON411

Locations and reports

Radon Levels in Brown County, Indiana

EPA puts Brown County in Zone 2, its middle radon zone, and 25.9% of its 112 reported radon tests (2008 to 2017, laboratory totals) were 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

    25.9%

    13.0 pts below IN

    Brown
    25.9%
    Indiana
    38.9%

    112 tests, 2008 to 2017

  • Median result

    2.8pCi/L

    Below action level

    Brown
    2.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    112

    43rd of 69 by tests

    Brown
    112
    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

    65 of 69

    Lowest quarter

    Brown
    25.9%
    Miami
    63.3%

    By share, of 69 with 30+ tests

Read a result for Brown County

Starts at Brown County's median, 2.8 pCi/L

2.8pCi/L

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

EPA’s reading of 2.8 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. Brown County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Brown County, At a glance

Brown County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Brown 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 99% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Brown County, 2008 to 2017, laboratory
Under 2 pCi/L: 37%2 to 4 pCi/L: 37%4 pCi/L and above: 26%

Of 112 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Brown County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L4237.5%
2 to 4 pCi/L4136.6%
4 pCi/L and above2925.9%
What these figures count

These are the 112 tests reported to CDC for Brown 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

Brown County, Compared

Brown County radon figures, compared

Calculated by Radon411

Brown County's 112 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.8 pCi/L and a maximum of 42.2 pCi/L, and 25.9% reached 4 pCi/L. Indiana as a whole (92 Indiana counties, pooled) comes to 38.9%: 13.0 points higher than here.

Among its state's counties it ranks 65th of 69 Indiana counties with 30 or more tests for the same period. Statewide for the same period, Miami County reported the highest share (63.3%) and Jasper County the lowest (14.1%).

Below the action level, 42 tests (37.5%) came in under 2 pCi/L, against 32.8% statewide, and 41 tests (36.6%) fell between 2 and 4, against 28.3% statewide. CDC's ten-year totals for Brown County went from 73 tests (2005 to 2014) to 112 (2008 to 2017), the share going from 28.8% to 25.9%.

EPA's 1993 zone map puts Brown County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 99% of the county's land moderate radon potential.

Next door, the shares run from 27.3% in Jackson County to 48.7% in Bartholomew County.

CDC also counts 5 tests taken after mitigation in Brown County for the same period: tests in homes where a fix was already in.

Brown County against Indiana, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Brown County
Brown County11225.9%2.8 pCi/LThis county
Indiana, pooled92 counties, pooled43,14838.9%Not pooled+13.0 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+9.8 points
Miami Countyhighest in the state3063.3%5.3 pCi/L+37.4 points
Jasper Countylowest in the state7114.1%1.2 pCi/L−11.8 points
Bartholomew County, INborders it1,70748.7%3.9 pCi/L+22.8 points
Morgan County, INborders it22644.2%3.5 pCi/L+18.3 points
Johnson County, INborders it55639.4%2.9 pCi/L+13.5 points
Monroe County, INborders it2,37534.2%2.8 pCi/L+8.3 points
Jackson County, INborders it8827.3%2.8 pCi/L+1.4 points
Where Brown County's reported results fell, 2008 to 2017, laboratory, beside Indiana and the United States
ResultBrown County testsBrown County shareIndiana shareU.S. shareAgainst Indiana
Under 2 pCi/L4237.5%32.8%39.6%+4.7 points
2 to 4 pCi/L4136.6%28.3%24.7%+8.3 points
4 pCi/L and above2925.9%38.9%35.7%−13.0 points
Brown 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
Decatur County59 of 696333.3%2.8 pCi/L
Greene County60 of 694932.7%3.0 pCi/L
Dearborn County61 of 6913630.1%2.6 pCi/L
St. Joseph County62 of 697,34629.3%2.7 pCi/L
Franklin County63 of 695028.0%2.1 pCi/L
Jackson County64 of 698827.3%2.8 pCi/L
Brown County65 of 6911225.9%2.8 pCi/L
Vanderburgh County66 of 691,50524.4%2.4 pCi/L
Lake County67 of 691,19823.5%1.8 pCi/L
Warrick County68 of 6956120.9%1.8 pCi/L
Jasper County69 of 697114.1%1.2 pCi/L
Brown County ten-year laboratory totals, against Indiana's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIndiana, pooledChange from the row before
2008 to 201711225.9%2.8 pCi/L42.2 pCi/L38.9%−1.7 points
2007 to 20169827.6%2.9 pCi/L42.2 pCi/L39.2%−1.0 points
2006 to 20158428.6%2.9 pCi/L42.2 pCi/L39.6%−0.2 points
2005 to 20147328.8%2.8 pCi/L9.4 pCi/L39.3%First on file

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

Brown County, Geology

The ground under Brown County

Predicted

Most of the ground under Brown County is one class on USGS's geologic map: 99.3% of its land is moderate radon potential, with 0.7% high. 99.3% of it lies in the area the map calls Crawford Upland/Mitchell Plain/Norman Upland, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Brown County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Crawford Upland/Mitchell Plain/Norman UplandUnglaciated, underlain by karsted Mississippian carbonate rocks.Moderate1199.3%
Huron-Erie LobeCalcareous clayey and loamy glacial deposits derived from marine carbonate and clastic sedimentary rocks.High130.7%

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

Brown County beside the ground around it

Indiana as a whole has more high-potential ground than Brown County: 56.6% of its land, against 0.7% here. Of the 5 counties that border it, 4 have more high-potential ground, Johnson County the most at 99.1%.

Share of land by USGS radon potential: Brown County, the 5 counties bordering it and Indiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Brown CountyZone 2None99.3%0.7%
Monroe CountyZone 1None100%None
Bartholomew CountyZone 1None29.3%70.7%
Jackson CountyZone 2None79.6%20.4%
Johnson CountyZone 1None0.9%99.1%
Morgan CountyZone 2None44.4%55.6%
Indiana92 counties, pooled by land areaVariesNone43.4%56.6%

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

Local help

Brown County, Local resources

Radon testing and mitigation in Brown 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

Brown County, Questions

Questions about radon in Brown County

Are radon levels high in Brown County?

Over the 2008 to 2017 laboratory totals, 25.9% of the radon tests reported to CDC for Brown County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 64 reported a higher share; pooled, the state comes to 38.9%.

Which counties border Brown County?

Brown County borders 5 counties: Monroe County, Bartholomew County, Jackson County, Johnson County and Morgan County.

Products

Brown County, Products

Testing a home in Brown County

In Brown County, 25.9% of 112 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 Brown County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Brown County homes, compared

Explore

Brown County, Bordering counties

Counties bordering Brown County

Calculated by Radon411

Brown County, Cities and towns

Cities and towns in Brown County

The Census Bureau estimates 15,777 residents in Brown County for July 1, 2025, 296 more than in 2020 (+1.9%). That works out to 51 people per square mile of land. Nashville, its one incorporated place, has 1,273 residents, 8.1% of the total. CDC's 112 reported tests for 2008 to 2017 work out to 7.1 per 1,000 residents (2025 estimate), close to Indiana's 6.2.

Nashville is the one incorporated place here; CDC publishes no figure by town, so it reads Brown County's.

Nashville, Brown County: residents on July 1, 2025
PlaceResidentsSince 2020Share of residents
Nashville1,273+1.5%8.1%

One incorporated place, 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).

Brown County, Homes

Homes in Brown County

Brown County is a place of houses on their own lots: 87% of its 8,540 homes are detached single-family houses, against 73% across Indiana. Half of its homes were built before 1982, close to Indiana's 1976: 19% date from before 1960 and 26% from 2000 or later. Owners live in 86% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.

Homes in Brown County, Indiana, 2019 to 2023
HomesBrown CountyIndiana
Housing units8,5402,953,344
Detached houses87%73%
In buildings of 5 or more4%13%
Mobile homes6%4%
Built before 196019%32%
Built since 200026%21%
Middle year built19821976
Owner-occupied86%70%

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