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Radon Levels in Allen County, Indiana

EPA puts Allen County in Zone 1, its highest radon zone, and high results are common there: 41.8% of the 3,990 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

    41.8%

    2.9 pts above IN

    Allen
    41.8%
    Indiana
    38.9%

    3,990 tests, 2008 to 2017

  • Median result

    3.3pCi/L

    Below action level

    Allen
    3.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    3,990

    2nd of 69 by tests

    Allen
    3,990
    St. Joseph
    7,346

    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 Indiana

    38 of 69

    Middle half

    Allen
    41.8%
    Miami
    63.3%

    By share, of 69 with 30+ tests

Read a result for Allen County

Starts at Allen County's median, 3.3 pCi/L

3.3pCi/L

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

EPA’s reading of 3.3 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. Allen County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Allen County, At a glance

Allen County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Allen 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Allen County, 2008 to 2017, laboratory
Under 2 pCi/L: 29%2 to 4 pCi/L: 29%4 pCi/L and above: 42%

Of 3,990 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Allen County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L1,15829.0%
2 to 4 pCi/L1,16529.2%
4 pCi/L and above1,66741.8%
What these figures count

These are the 3,990 tests reported to CDC for Allen 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

Allen County, Compared

Allen County radon figures, compared

Calculated by Radon411

In Allen County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (1,667 of 3,990) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 6.1 points higher. Across 92 Indiana counties pooled together, 38.9% of tests reached that level, so Allen County runs 2.9 points above its state.

Of 7 neighbours with a figure, all 7 reported a larger share at or above 4 pCi/L; the spread is 43.8% (Huntington County) to 56.6% (DeKalb County). By share, Allen County is 38th of 69 Indiana counties with 30 or more tests for the same period.

Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 98.9 pCi/L. Below the action level, 1,158 tests (29.0%) came in under 2 pCi/L, against 32.8% statewide, and 1,165 tests (29.2%) fell between 2 and 4, against 28.3% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 41.8% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 394 tests taken after mitigation in Allen County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Allen County went from 3,109 tests (2005 to 2014) to 3,990 (2008 to 2017), the share going from 41.9% to 41.8%.

Allen County against Indiana, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Allen County
Allen County3,99041.8%3.3 pCi/LThis county
Indiana, pooled92 counties, pooled43,14838.9%Not pooled−2.9 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−6.1 points
Miami Countyhighest in the state3063.3%5.3 pCi/L+21.5 points
Jasper Countylowest in the state7114.1%1.2 pCi/L−27.7 points
DeKalb County, INborders it24256.6%4.4 pCi/L+14.8 points
Van Wert County, OHborders it2653.8%4.3 pCi/L+12.0 points
Noble County, INborders it13652.9%4.3 pCi/L+11.1 points
Whitley County, INborders it18451.6%4.0 pCi/L+9.8 points
Defiance County, OHborders it7048.6%3.8 pCi/L+6.8 points
Adams County, INborders it6648.5%3.8 pCi/L+6.7 points
Wells County, INborders it16147.8%3.6 pCi/L+6.0 points
Huntington County, INborders it16943.8%3.5 pCi/L+2.0 points
Paulding County, OHborders it1323.1%3.2 pCi/L−18.7 points
Where Allen County's reported results fell, 2008 to 2017, laboratory, beside Indiana and the United States
ResultAllen County testsAllen County shareIndiana shareU.S. shareAgainst Indiana
Under 2 pCi/L1,15829.0%32.8%39.6%−3.8 points
2 to 4 pCi/L1,16529.2%28.3%24.7%+0.9 points
4 pCi/L and above1,66741.8%38.9%35.7%+2.9 points
Allen 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
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
Hendricks County40 of 691,17041.5%3.2 pCi/L
Montgomery County41 of 6915241.4%2.9 pCi/L
Marion County42 of 693,66840.1%3.1 pCi/L
Boone County43 of 6961439.7%3.0 pCi/L
Allen County ten-year laboratory totals, against Indiana's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIndiana, pooledChange from the row before
2008 to 20173,99041.8%3.3 pCi/L98.9 pCi/L38.9%−0.1 points
2007 to 20163,63141.9%3.3 pCi/L93.3 pCi/L39.2%+0.1 points
2006 to 20153,39841.8%3.3 pCi/L93.3 pCi/L39.6%−0.1 points
2005 to 20143,10941.9%3.3 pCi/L92.6 pCi/L39.3%First on file

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

Allen County, Geology

The ground under Allen County

Predicted

USGS's geologic map puts all of Allen County's mapped land in one class: high radon potential. All of it lies in the area the map calls Huron-Erie Lobe, to which USGS gives a radon index of 13, in the high band (12 to 17).

USGS's geologic areas under Allen County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Huron-Erie LobeCalcareous clayey and loamy glacial deposits derived from marine carbonate and clastic sedimentary rocks.High1399.9%

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

Allen County beside the ground around it

Allen County has more high-potential ground than Indiana as a whole: 100% of its land against 56.6%. Of the 9 counties that border it, none has as large a share of high-potential ground; Adams County comes nearest at 100%.

Share of land by USGS radon potential: Allen County, the 9 counties bordering it and Indiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Allen CountyZone 1NoneNone100%
DeKalb CountyZone 1NoneNone100%
Adams CountyZone 1NoneNone100%
Wells CountyZone 1NoneNone100%
Whitley CountyZone 1NoneNone100%
Paulding County, OHZone 2None57.6%42.4%
Noble CountyZone 1NoneNone100%
Huntington CountyZone 1NoneNone100%
Van Wert County, OHZone 1None0.1%99.9%
Defiance County, OHZone 2None37.4%62.6%
Indiana92 counties, pooled by land areaVariesNone43.4%56.6%

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

Local help

Allen County, Local resources

Radon testing and mitigation in Allen 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

Allen County, Questions

Questions about radon in Allen County

Are radon levels high in Allen County?

Over the 2008 to 2017 laboratory totals, 41.8% of the radon tests reported to CDC for Allen County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 37 reported a higher share; pooled, the state comes to 38.9%.

Which counties border Allen County?

Allen County borders 9 counties: DeKalb County, IN, Adams County, IN, Wells County, IN, Whitley County, IN, Paulding County, OH, Noble County, IN, Huntington County, IN, Van Wert County, OH and Defiance County, OH.

Products

Allen County, Products

Testing a home in Allen County

In Allen County, 41.8% of 3,990 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 38.9% pooled across Indiana. In Zone 1 the year-round level in Allen 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

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

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Allen County, Bordering counties

Counties bordering Allen County

Calculated by Radon411

Allen County, Cities and towns

Cities and towns in Allen County

The Census Bureau estimates 402,329 residents in Allen County for July 1, 2025, 16,222 more than in 2020 (+4.2%). That works out to 612 people per square mile of land. Fort Wayne alone is home to 275,203 of them, 68.4% of the total. Testing is reported here more often than across the state: CDC's 3,990 reported tests for 2008 to 2017 come to 9.9 for every 1,000 residents (2025 estimate), against 6.2 for Indiana.

From Fort Wayne to Zanesville, CDC publishes no figure by town: each reads Allen County's.

The cities and towns in Allen County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Fort Wayne275,203+4.1%68.4%
New Haven16,337+4.5%4.1%
Huntertown11,600+4.4%2.9%
Leo-Cedarville3,790+4.2%0.9%
Woodburn1,628+4.5%0.4%
Monroeville1,355+4.2%0.3%
Grabill1,168+4.7%0.3%
Zanesvilleextends beyond Allen County600+3.3%Counted whole

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). A place that extends beyond Allen County is counted whole, so it has no share.

Allen County, Homes

Homes in Allen County

Of Allen County's 164,456 homes, 74% are detached houses, against 73% across Indiana; 15% are in buildings of five or more homes. Half of its homes were built before 1976, close to Indiana's 1976: 28% date from before 1960 and 20% from 2000 or later. 69% of occupied homes are lived in by their owner (Indiana: 70%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Allen County, Indiana, 2019 to 2023
HomesAllen CountyIndiana
Housing units164,4562,953,344
Detached houses74%73%
In buildings of 5 or more15%13%
Mobile homes3%4%
Built before 196028%32%
Built since 200020%21%
Middle year built19761976
Owner-occupied69%70%

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