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Radon Levels in Wapello County, Iowa

EPA puts Wapello County in Zone 1, its highest radon zone, and 35.9% of its 287 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

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  • Share at 4+ pCi/L

    35.9%

    22.6 pts below IA

    Wapello
    35.9%
    Iowa
    58.5%

    287 tests, 2008 to 2017

  • Median result

    2.7pCi/L

    Below action level

    Wapello
    2.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    287

    74th of 99 by tests

    Wapello
    287
    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

    93 of 99

    Lowest quarter

    Wapello
    35.9%
    Sioux
    84.2%

    By share, of 99 with 30+ tests

Read a result for Wapello County

Starts at Wapello County's median, 2.7 pCi/L

2.7pCi/L

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

EPA’s reading of 2.7 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. Wapello County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Wapello County, At a glance

Wapello County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Wapello County, 2008 to 2017, laboratory
Under 2 pCi/L: 38%2 to 4 pCi/L: 26%4 pCi/L and above: 36%

Of 287 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Wapello County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L10837.6%
2 to 4 pCi/L7626.5%
4 pCi/L and above10335.9%
What these figures count

These are the 287 tests reported to CDC for Wapello 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

Wapello County, Compared

Wapello County radon figures, compared

Calculated by Radon411

In Wapello County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (103 of 287) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 0.2 points higher. Across 99 Iowa counties pooled together, 58.5% of tests reached that level, so Wapello County runs 22.6 points below its state.

Of 7 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 32.1% (Van Buren County) to 61.1% (Mahaska County). By share, Wapello County is 93rd of 99 Iowa counties with 30 or more tests for the same period.

Half the tests came in under 2.7 pCi/L and half over it; the single highest reached 32.8 pCi/L. Below the action level, 108 tests (37.6%) came in under 2 pCi/L, against 21.8% statewide, and 76 tests (26.5%) fell between 2 and 4, against 19.7% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 35.9% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 9 tests taken after mitigation in Wapello County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Wapello County went from 313 tests (2005 to 2014) to 287 (2008 to 2017), the share going from 34.8% to 35.9%.

Wapello County against Iowa, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Wapello County
Wapello County28735.9%2.7 pCi/LThis county
Iowa, pooled99 counties, pooled95,24558.5%Not pooled+22.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−0.2 points
Sioux Countyhighest in the state1,98284.2%10.7 pCi/L+48.3 points
Decatur Countylowest in the state8525.9%2.5 pCi/L−10.0 points
Mahaska County, IAborders it28861.1%5.2 pCi/L+25.2 points
Keokuk County, IAborders it21460.3%5.2 pCi/L+24.4 points
Appanoose County, IAborders it11745.3%3.7 pCi/L+9.4 points
Davis County, IAborders it8542.4%3.1 pCi/L+6.5 points
Monroe County, IAborders it5933.9%2.9 pCi/L−2.0 points
Jefferson County, IAborders it84133.5%2.6 pCi/L−2.4 points
Van Buren County, IAborders it5632.1%2.3 pCi/L−3.8 points
Where Wapello County's reported results fell, 2008 to 2017, laboratory, beside Iowa and the United States
ResultWapello County testsWapello County shareIowa shareU.S. shareAgainst Iowa
Under 2 pCi/L10837.6%21.8%39.6%+15.8 points
2 to 4 pCi/L7626.5%19.7%24.7%+6.8 points
4 pCi/L and above10335.9%58.5%35.7%−22.6 points
Wapello 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
Lee County88 of 9935143.6%3.2 pCi/L
Davis County89 of 998542.4%3.1 pCi/L
Johnson County90 of 997,32141.6%3.2 pCi/L
Linn County91 of 999,39539.7%3.0 pCi/L
Lucas County92 of 998439.3%3.3 pCi/L
Wapello County93 of 9928735.9%2.7 pCi/L
Wayne County94 of 994634.8%3.0 pCi/L
Monroe County95 of 995933.9%2.9 pCi/L
Jefferson County96 of 9984133.5%2.6 pCi/L
Van Buren County97 of 995632.1%2.3 pCi/L
Ringgold County98 of 998728.7%2.6 pCi/L
Wapello County ten-year laboratory totals, against Iowa's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIowa, pooledChange from the row before
2008 to 201728735.9%2.7 pCi/L32.8 pCi/L58.5%+0.5 points
2007 to 201628535.4%2.7 pCi/L32.8 pCi/L58.6%+0.3 points
2006 to 201530235.1%2.7 pCi/L95.2 pCi/L59.4%+0.3 points
2005 to 201431334.8%2.7 pCi/L95.2 pCi/L59.6%First on file

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

Wapello County, Geology

The ground under Wapello County

Predicted

USGS's geologic map puts all of Wapello 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 Wapello County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Loess-Covered Drift PlainsPre-Illinoian and Illinoian glacial deposits, and loess.High13100%

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

Wapello County beside the ground around it

On high-potential ground Wapello County is close to Iowa as a whole: 100% of its land against 98.8%. Of the 7 counties that border it, none has as large a share of high-potential ground; Jefferson County comes nearest at 100%.

Share of land by USGS radon potential: Wapello County, the 7 counties bordering it and Iowa
AreaEPA zoneLow potentialModerate potentialHigh potential
Wapello CountyZone 1NoneNone100%
Davis CountyZone 1None42.9%57.1%
Monroe CountyZone 1NoneNone100%
Jefferson CountyZone 1NoneNone100%
Mahaska CountyZone 1NoneNone100%
Keokuk CountyZone 1NoneNone100%
Appanoose CountyZone 1None46.5%53.5%
Van Buren CountyZone 1None8.8%91.2%
Iowa99 counties, pooled by land areaVariesNone1.2%98.8%

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

Local help

Wapello County, Local resources

Radon testing and mitigation in Wapello 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

Wapello County, Questions

Questions about radon in Wapello County

Are radon levels high in Wapello County?

Over the 2008 to 2017 laboratory totals, 35.9% of the radon tests reported to CDC for Wapello County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.7 pCi/L. Of 99 Iowa counties with 30 or more tests for the same period, 92 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Wapello County?

Wapello County borders 7 counties: Davis County, Monroe County, Jefferson County, Mahaska County, Keokuk County, Appanoose County and Van Buren County.

Products

Wapello County, Products

Testing a home in Wapello County

In Wapello County, 35.9% of 287 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 Wapello 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

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

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Wapello County, Bordering counties

Counties bordering Wapello County

Calculated by Radon411

Wapello County, Cities and towns

Cities and towns in Wapello County

Wapello County's population has barely moved since 2020: 35,210 residents on July 1, 2025 against 35,334 then, by the Census Bureau's estimates. That works out to 82 people per square mile of land. Ottumwa alone is home to 25,319 of them, 71.9% of the total. Reported testing is thin here: 287 tests over 2008 to 2017, or 8.2 for every 1,000 residents (2025 estimate), where Iowa as a whole comes to 29.4.

From Ottumwa to Chillicothe, CDC publishes no figure by town: each reads Wapello County's.

The cities and towns in Wapello County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Ottumwa25,319−0.6%71.9%
Eddyvilleextends beyond Wapello County960−0.7%Counted whole
Eldon776−1.1%2.2%
Agency612−0.5%1.7%
Blakesburg263−1.5%0.7%
Kirkville159+2.6%0.5%
Chillicothe75−1.3%0.2%

7 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 Wapello County is counted whole, so it has no share.

Wapello County, Homes

Homes in Wapello County

Wapello County is a place of houses on their own lots: 78% of its 15,740 homes are detached single-family houses, against 72% across Iowa. The homes are older than Iowa's as a whole: half were built before 1958 (1971 for Iowa), and 54% date from before 1960. 67% of occupied homes are lived in by their owner (Iowa: 72%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Wapello County, Iowa, 2019 to 2023
HomesWapello CountyIowa
Housing units15,7401,427,175
Detached houses78%72%
In buildings of 5 or more11%14%
Mobile homes4%3%
Built before 196054%39%
Built since 20008%21%
Middle year built19581971
Owner-occupied67%72%

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