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Radon Levels in Wright County, Iowa

EPA puts Wright County in Zone 1, its highest radon zone, and high results are common there: 66.8% of the 292 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

    66.8%

    8.3 pts above IA

    Wright
    66.8%
    Iowa
    58.5%

    292 tests, 2008 to 2017

  • Median result

    6.2pCi/L

    Action level reached

    Wright
    6.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    292

    72nd of 99 by tests

    Wright
    292
    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

    45 of 99

    Middle half

    Wright
    66.8%
    Sioux
    84.2%

    By share, of 99 with 30+ tests

Read a result for Wright County

Starts at Wright County's median, 6.2 pCi/L

6.2pCi/L

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

EPA’s reading of 6.2 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. Wright County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Wright County, At a glance

Wright County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Wright County, 2008 to 2017, laboratory
Under 2 pCi/L: 15%2 to 4 pCi/L: 18%4 pCi/L and above: 67%

Of 292 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Wright County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L4515.4%
2 to 4 pCi/L5217.8%
4 pCi/L and above19566.8%
What these figures count

These are the 292 tests reported to CDC for Wright 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

Wright County, Compared

Wright County radon figures, compared

Calculated by Radon411

More than half: 66.8% of the 292 radon tests reported to CDC for Wright County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 45th of 99 Iowa counties with 30 or more tests for the same period. That is 8.3 points above the 58.5% pooled from 99 Iowa counties.

The median result, 6.2 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 113.0 pCi/L. The rest split 15.4% under 2 pCi/L and 17.8% from 2 to 4 (Iowa: 21.8% and 19.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 66.8% share point the same way here.

3 of its 8 bordering counties with figures ran higher, led by Franklin County at 73.5%; Cerro Gordo County reported 59.0%. 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 Wright County went from 215 tests (2005 to 2014) to 292 (2008 to 2017), the share going from 67.4% to 66.8%.

Nationally, every county with a figure for the same period pools to 35.7%; Wright County sits 31.1 points above it. CDC also counts 31 tests taken after mitigation in Wright County for the same period: tests in homes where a fix was already in.

Wright County against Iowa, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Wright County
Wright County29266.8%6.2 pCi/LThis county
Iowa, pooled99 counties, pooled95,24558.5%Not pooled−8.3 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−31.1 points
Sioux Countyhighest in the state1,98284.2%10.7 pCi/L+17.4 points
Decatur Countylowest in the state8525.9%2.5 pCi/L−40.9 points
Franklin County, IAborders it31373.5%6.2 pCi/L+6.7 points
Humboldt County, IAborders it38570.1%7.0 pCi/L+3.3 points
Webster County, IAborders it1,18969.4%6.5 pCi/L+2.6 points
Kossuth County, IAborders it43466.1%5.7 pCi/L−0.7 points
Hancock County, IAborders it64064.5%5.5 pCi/L−2.3 points
Hamilton County, IAborders it25264.3%5.5 pCi/L−2.5 points
Hardin County, IAborders it34962.8%5.6 pCi/L−4.0 points
Cerro Gordo County, IAborders it1,66259.0%4.8 pCi/L−7.8 points
Where Wright County's reported results fell, 2008 to 2017, laboratory, beside Iowa and the United States
ResultWright County testsWright County shareIowa shareU.S. shareAgainst Iowa
Under 2 pCi/L4515.4%21.8%39.6%−6.4 points
2 to 4 pCi/L5217.8%19.7%24.7%−1.9 points
4 pCi/L and above19566.8%58.5%35.7%+8.3 points
Wright 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
Worth County40 of 9915467.5%6.0 pCi/L
Montgomery County41 of 9923367.4%6.1 pCi/L
Marion County42 of 991,15167.3%6.0 pCi/L
Osceola County43 of 9912267.2%6.8 pCi/L
Grundy County44 of 9950166.9%6.9 pCi/L
Wright County45 of 9929266.8%6.2 pCi/L
Winneshiek County46 of 991,07166.4%6.2 pCi/L
Kossuth County47 of 9943466.1%5.7 pCi/L
Warren County48 of 991,51366.0%6.3 pCi/L
Adams County49 of 998165.4%6.1 pCi/L
Hancock County50 of 9964064.5%5.5 pCi/L
Wright County ten-year laboratory totals, against Iowa's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIowa, pooledChange from the row before
2008 to 201729266.8%6.2 pCi/L113.0 pCi/L58.5%−1.0 points
2007 to 201626167.8%6.2 pCi/L113.0 pCi/L58.6%−0.5 points
2006 to 201526268.3%6.5 pCi/L113.0 pCi/L59.4%+0.9 points
2005 to 201421567.4%6.2 pCi/L113.0 pCi/L59.6%First on file

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

Wright County, Geology

The ground under Wright County

Predicted

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

USGS's geologic areas under Wright County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Des Moines LobeCalcareous loamy till derived from shale, limestone, dolomite, sandstone.High12100%

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

Wright County beside the ground around it

On high-potential ground Wright County is close to Iowa as a whole: 100% of its land against 98.8%. Of the 8 counties that border it, none has as large a share of high-potential ground; Cerro Gordo County comes nearest at 100%.

Share of land by USGS radon potential: Wright County, the 8 counties bordering it and Iowa
AreaEPA zoneLow potentialModerate potentialHigh potential
Wright CountyZone 1NoneNone100%
Hancock CountyZone 1NoneNone100%
Humboldt CountyZone 1NoneNone100%
Franklin CountyZone 1NoneNone100%
Hamilton CountyZone 1NoneNone100%
Cerro Gordo CountyZone 1NoneNone100%
Kossuth CountyZone 1NoneNone100%
Webster CountyZone 1NoneNone100%
Hardin CountyZone 1NoneNone100%
Iowa99 counties, pooled by land areaVariesNone1.2%98.8%

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

Local help

Wright County, Local resources

Radon testing and mitigation in Wright 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

Wright County, Questions

Questions about radon in Wright County

Are radon levels high in Wright County?

Over the 2008 to 2017 laboratory totals, 66.8% of the radon tests reported to CDC for Wright County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.2 pCi/L. Of 99 Iowa counties with 30 or more tests for the same period, 44 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Wright County?

Wright County borders 8 counties: Hancock County, Humboldt County, Franklin County, Hamilton County, Cerro Gordo County, Kossuth County, Webster County and Hardin County.

Products

Wright County, Products

Testing a home in Wright County

In Wright County, 66.8% of 292 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 Wright 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

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

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Wright County, Bordering counties

Counties bordering Wright County

Calculated by Radon411

Wright County, Cities and towns

Cities and towns in Wright County

About 12,801 people live in Wright County by the Census Bureau's estimate for July 1, 2025, 118 fewer than in 2020 (−0.9%). That works out to 22 people per square mile of land. Its largest town, Eagle Grove, has 3,653 residents, 28.5% of the total. CDC's 292 reported tests for 2008 to 2017 work out to 22.8 per 1,000 residents (2025 estimate), close to Iowa's 29.4.

From Eagle Grove to Galt, CDC publishes no figure by town: each reads Wright County's.

The cities and towns in Wright County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Eagle Grove3,653+1.4%28.5%
Clarion2,758−1.6%21.5%
Belmond2,420−1.7%18.9%
Goldfield616−2.5%4.8%
Dowsextends beyond Wright County513−2.3%Counted whole
Woolstock140−2.1%1.1%
Rowan118−3.3%0.9%
Galt23Level0.2%

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

Wright County, Homes

Homes in Wright County

Wright County is a place of houses on their own lots: 85% of its 6,266 homes are detached single-family houses, against 72% across Iowa. The homes are older than Iowa's as a whole: half were built before 1957 (1971 for Iowa), and 54% date from before 1960. 74% 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 Wright County, Iowa, 2019 to 2023
HomesWright CountyIowa
Housing units6,2661,427,175
Detached houses85%72%
In buildings of 5 or more7%14%
Mobile homes1%3%
Built before 196054%39%
Built since 20009%21%
Middle year built19571971
Owner-occupied74%72%

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