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Radon Levels in Mills County, Iowa

EPA puts Mills County in Zone 1, its highest radon zone, and high results are common there: 70.1% of the 465 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

    70.1%

    11.6 pts above IA

    Mills
    70.1%
    Iowa
    58.5%

    465 tests, 2008 to 2017

  • Median result

    6.1pCi/L

    Action level reached

    Mills
    6.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    465

    51st of 99 by tests

    Mills
    465
    Polk
    10,945

    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 Iowa

    31 of 99

    Middle half

    Mills
    70.1%
    Sioux
    84.2%

    By share, of 99 with 30+ tests

Read a result for Mills County

Starts at Mills County's median, 6.1 pCi/L

6.1pCi/L

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

EPA’s reading of 6.1 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Mills County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Mills County, At a glance

Mills County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Mills 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 Mills County, 2008 to 2017, laboratory

Reported results by concentration band, Mills County, 2008 to 2017, laboratory
Under 2 pCi/L: 12%2 to 4 pCi/L: 18%4 pCi/L and above: 70%

Of 465 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Mills County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L5511.8%
2 to 4 pCi/L8418.1%
4 pCi/L and above32670.1%
What these figures count

These are the 465 tests reported to CDC for Mills 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

Mills County, Compared

Mills County radon figures, compared

Calculated by Radon411

More than half: 70.1% of the 465 radon tests reported to CDC for Mills County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 31st of 99 Iowa counties with 30 or more tests for the same period. That is 11.6 points above the 58.5% pooled from 99 Iowa counties.

The median result, 6.1 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 53.2 pCi/L. The rest split 11.8% under 2 pCi/L and 18.1% from 2 to 4 (Iowa: 21.8% and 19.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 70.1% share point the same way here.

1 of its 6 bordering counties with figures ran higher, led by Page County at 71.7%; Sarpy County, NE reported 53.6%. Statewide for the same period, Sioux County reported the highest share (84.2%) and Decatur County the lowest (25.9%).

CDC's ten-year totals for Mills County went from 319 tests (2005 to 2014) to 465 (2008 to 2017), the share going from 75.2% to 70.1%.

Nationally, every county with a figure for the same period pools to 35.7%; Mills County sits 34.4 points above it. CDC also counts 64 tests taken after mitigation in Mills County for the same period: tests in homes where a fix was already in.

Mills County against Iowa, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Mills County
Mills County46570.1%6.1 pCi/LThis county
Iowa, pooled99 counties, pooled95,24558.5%Not pooled−11.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−34.4 points
Sioux Countyhighest in the state1,98284.2%10.7 pCi/L+14.1 points
Decatur Countylowest in the state8525.9%2.5 pCi/L−44.2 points
Page County, IAborders it65371.7%7.2 pCi/L+1.6 points
Fremont County, IAborders it20569.8%7.2 pCi/L−0.3 points
Montgomery County, IAborders it23367.4%6.1 pCi/L−2.7 points
Cass County, NEborders it62066.0%6.3 pCi/L−4.1 points
Pottawattamie County, IAborders it1,86857.4%4.7 pCi/L−12.7 points
Sarpy County, NEborders it4,79953.6%4.3 pCi/L−16.5 points
Where Mills County's reported results fell, 2008 to 2017, laboratory, beside Iowa and the United States
ResultMills County testsMills County shareIowa shareU.S. shareAgainst Iowa
Under 2 pCi/L5511.8%21.8%39.6%−10.0 points
2 to 4 pCi/L8418.1%19.7%24.7%−1.6 points
4 pCi/L and above32670.1%58.5%35.7%+11.6 points
Mills County ranked among the 99 Iowa counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Mitchell County26 of 9944470.7%6.4 pCi/L
Poweshiek County27 of 9941970.6%7.2 pCi/L
Dickinson County28 of 9983170.3%7.0 pCi/L
Marshall County29 of 9957070.2%8.2 pCi/L
Humboldt County30 of 9938570.1%7.0 pCi/L
Mills County31 of 9946570.1%6.1 pCi/L
Calhoun County32 of 9950769.8%6.1 pCi/L
Fremont County33 of 9920569.8%7.2 pCi/L
Harrison County34 of 9936769.8%6.2 pCi/L
Webster County35 of 991,18969.4%6.5 pCi/L
Woodbury County36 of 993,54169.2%6.1 pCi/L
Mills County ten-year laboratory totals, against Iowa's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIowa, pooledChange from the row before
2008 to 201746570.1%6.1 pCi/L53.2 pCi/L58.5%+0.5 points
2007 to 201645169.6%6.0 pCi/L53.2 pCi/L58.6%−1.1 points
2006 to 201537570.7%6.1 pCi/L49.2 pCi/L59.4%−4.5 points
2005 to 201431975.2%6.6 pCi/L49.2 pCi/L59.6%First on file

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

Mills County, Geology

The ground under Mills County

Predicted

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

USGS's geologic areas under Mills County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Loess-Covered Drift PlainsPre-Illinoian and Illinoian glacial deposits, and loess.High1399.6%

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

Mills County beside the ground around it

On high-potential ground Mills County is close to Iowa as a whole: 100% of its land against 98.8%. Of the 6 counties that border it, none has as large a share of high-potential ground; Cass County, NE comes nearest at 100%.

Share of land by USGS radon potential: Mills County, the 6 counties bordering it and Iowa
AreaEPA zoneLow potentialModerate potentialHigh potential
Mills CountyZone 1NoneNone100%
Fremont CountyZone 1NoneNone100%
Pottawattamie CountyZone 1NoneNone100%
Montgomery CountyZone 1NoneNone100%
Sarpy County, NEZone 1NoneNone100%
Cass County, NEZone 1NoneNone100%
Page CountyZone 1NoneNone100%
Iowa99 counties, pooled by land areaVariesNone1.2%98.8%

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

Local help

Mills County, Local resources

Radon testing and mitigation in Mills County

What Iowa's program says
Phone
(515) 281-4928
Licensing of radon professionals
Iowa’s radon program approves applications for persons who wish to become certified to perform radon testing or credentialed to perform mitigation and laboratories that provide radon testing devices and analytical services.
Disclosure when a home is sold or rented
However, per Iowa Code chapters 543B.9 and 543B.18 and Iowa Administrative Code 193E Chapter 14 administered by the Iowa Real Estate Commission, a seller must disclose any known tests for the presence of radon and if yes, provide the date of last report and the result(s).

What it means

Mills County, Questions

Questions about radon in Mills County

Are radon levels high in Mills County?

Over the 2008 to 2017 laboratory totals, 70.1% of the radon tests reported to CDC for Mills County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.1 pCi/L. Of 99 Iowa counties with 30 or more tests for the same period, 30 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Mills County?

Mills County borders 6 counties: Fremont County, IA, Pottawattamie County, IA, Montgomery County, IA, Sarpy County, NE, Cass County, NE and Page County, IA.

Products

Mills County, Products

Testing a home in Mills County

In Mills County, 70.1% of 465 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 58.5% pooled across Iowa. In Zone 1 the year-round level in Mills 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

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

Explore

Mills County, Bordering counties

Counties bordering Mills County

Calculated by Radon411

Mills County, Cities and towns

Cities and towns in Mills County

The Census Bureau estimates 14,793 residents in Mills County for July 1, 2025, 380 more than in 2020 (+2.6%). That works out to 34 people per square mile of land. Its largest town, Glenwood, has 5,287 residents, 35.7% of the total. CDC's 465 reported tests for 2008 to 2017 work out to 31.4 per 1,000 residents (2025 estimate), close to Iowa's 29.4.

From Glenwood to Pacific Junction, CDC publishes no figure by town: each reads Mills County's.

The cities and towns in Mills County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Glenwood5,287+4.4%35.7%
Malvern1,073+4.1%7.3%
Taborextends beyond Mills County985−2.2%Counted whole
Emerson400+0.5%2.7%
Silver City246+2.5%1.7%
Hastings158+2.6%1.1%
Henderson137Level0.9%
Pacific Junction100+1.0%0.7%

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 Mills County is counted whole, so it has no share.

Mills County, Homes

Homes in Mills County

Mills County is a place of houses on their own lots: 84% of its 6,119 homes are detached single-family houses, against 72% across Iowa. Half of its homes were built before 1973, close to Iowa's 1971: 35% date from before 1960 and 18% from 2000 or later. Owners live in 84% of the occupied homes (Iowa: 72%), so for most households a test and a fix are their own to order.

Homes in Mills County, Iowa, 2019 to 2023
HomesMills CountyIowa
Housing units6,1191,427,175
Detached houses84%72%
In buildings of 5 or more3%14%
Mobile homes3%3%
Built before 196035%39%
Built since 200018%21%
Middle year built19731971
Owner-occupied84%72%

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