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Radon Levels in Dunn County, Wisconsin

EPA puts Dunn County in Zone 2, its middle radon zone, and 37.4% of its 171 reported radon tests (2023) 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

    37.4%

    1.7 pts above WI

    Dunn
    37.4%
    Wisconsin
    35.7%

    171 tests, 2023

  • Median result

    2.9pCi/L

    Below action level

    Dunn
    2.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    171

    32nd of 69 by tests

    Dunn
    171
    Dane
    2,887

    Reported to CDC before any fix, 2023

  • 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 Wisconsin

    36 of 69

    Middle half

    Dunn
    37.4%
    Langlade
    65.8%

    By share, of 69 with 30+ tests

Read a result for Dunn County

Starts at Dunn County's median, 2.9 pCi/L

2.9pCi/L

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

EPA’s reading of 2.9 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. Dunn County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Dunn County, At a glance

Dunn County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Dunn 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 90% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Dunn County, 2023

Share of reported tests at or above 4 pCi/L, by year, Dunn County
Share of reported tests at or above 4 pCi/L, by year, Dunn County
YearShare of reported tests at or above 4 pCi/L
201440.8%
201543.9%
201638.2%
201741.2%
201948.5%
202047.8%
202141.2%
202252.6%
202337.4%

2023: 37.4%. Across these years the share ran from 37.4% to 52.6%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 171 tests reported to CDC for Dunn County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Dunn County, Compared

Dunn County radon figures, compared

Calculated by Radon411

In Dunn County, about 4 in 10 reported tests in 2023 (64 of 171) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 4.0 points higher. Across 72 Wisconsin counties pooled together, 35.7% of tests reached that level, so Dunn County runs 1.7 points above its state.

Of 7 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 15.4% (Pepin County) to 37.4% (St. Croix County). By share, Dunn County is 36th of 69 Wisconsin counties with 30 or more tests for the same period.

Year by year, 2014 opened at 40.8% and 2023 closed at 37.4% (down 3.4 points), with 2022 the high at 52.6%. Half the tests came in under 2.9 pCi/L and half over it; the single highest reached 21.6 pCi/L. Below the action level, 66 tests (38.6%) came in under 2 pCi/L, against 41.4% statewide, and 41 tests (24.0%) fell between 2 and 4, against 23.0% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 37.4% share point the same way here. USGS geology rates 90% of the county's land moderate radon potential. CDC also counts 9 tests taken after mitigation in Dunn County for the same period: tests in homes where a fix was already in.

The busiest year on file was 2017, with 245 tests reported; the quietest, 2021, had 97.

Share of reported tests at or above 4 pCi/L by year, Dunn County against Wisconsin2014 to 2023, years with 30 or more tests: Dunn County 40.8% to 37.4%, the state's pooled share 35.7% in 2023.
Dunn CountyWisconsin, pooled
Share of reported tests at or above 4 pCi/L by year, Dunn County against Wisconsin: data table
YearTestsDunn County, at or above 4 pCi/LWisconsin, pooled
201413040.8%51.1%
201513243.9%51.6%
201621738.2%45.2%
201724541.2%44.8%
201910348.5%42.9%
202011347.8%27.0%
20219741.2%39.9%
202213752.6%42.9%
202317137.4%35.7%
Dunn County against Wisconsin, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Dunn County
Dunn County17137.4%2.9 pCi/LThis county
Wisconsin, pooled72 counties, pooled20,87935.7%Not pooled−1.7 points
United States, pooled642 counties, pooled128,74033.4%Not pooled−4.0 points
Langlade Countyhighest in the state22565.8%6.0 pCi/L+28.4 points
Bayfield Countylowest in the state355.7%1.5 pCi/L−31.7 points
St. Croix County, WIborders it34837.4%3.0 pCi/LLevel
Chippewa County, WIborders it31135.7%2.5 pCi/L−1.7 points
Barron County, WIborders it19934.7%2.5 pCi/L−2.7 points
Polk County, WIborders it12233.6%2.8 pCi/L−3.8 points
Eau Claire County, WIborders it47432.7%2.8 pCi/L−4.7 points
Pierce County, WIborders it13630.9%2.7 pCi/L−6.5 points
Pepin County, WIborders it6515.4%1.2 pCi/L−22.0 points
Where Dunn County's reported results fell, 2023, beside Wisconsin and the United States
ResultDunn County testsDunn County shareWisconsin shareU.S. shareAgainst Wisconsin
Under 2 pCi/L6638.6%41.4%41.4%−2.8 points
2 to 4 pCi/L4124.0%23.0%25.2%+1.0 points
4 pCi/L and above6437.4%35.7%33.4%+1.7 points
Dunn County ranked among the 69 Wisconsin counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
Green Lake County31 of 697940.5%3.4 pCi/L
Forest County32 of 694540.0%2.9 pCi/L
Jackson County33 of 699338.7%3.2 pCi/L
Rusk County34 of 695738.6%3.2 pCi/L
Walworth County35 of 6934037.9%2.8 pCi/L
Dunn County36 of 6917137.4%2.9 pCi/L
St. Croix County37 of 6934837.4%3.0 pCi/L
Racine County38 of 6944537.3%2.7 pCi/L
Price County39 of 696036.7%2.8 pCi/L
Chippewa County40 of 6931135.7%2.5 pCi/L
Portage County41 of 6933435.6%3.0 pCi/L
Dunn County radon tests by year, against Wisconsin's pooled share
YearTestsAt or above 4 pCi/LMedianHighestWisconsin, pooledChange from the row before
202317137.4%2.9 pCi/L21.6 pCi/L35.7%−15.2 points
202213752.6%4.1 pCi/L48.7 pCi/L42.9%+11.4 points
20219741.2%3.0 pCi/L75.1 pCi/L39.9%−6.6 points
202011347.8%3.7 pCi/L125.3 pCi/L27.0%−0.7 points
201910348.5%3.9 pCi/L66.1 pCi/L42.9%+7.3 points
201724541.2%3.4 pCi/L44.7 pCi/L44.8%+3.0 points
201621738.2%2.8 pCi/L44.7 pCi/L45.2%−5.7 points
201513243.9%3.3 pCi/L69.5 pCi/L51.6%+3.1 points
201413040.8%3.1 pCi/L68.3 pCi/L51.1%First on file

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

Dunn County, Geology

The ground under Dunn County

Predicted

Most of the ground under Dunn County is one class on USGS's geologic map: 90.3% of its land is moderate radon potential, with 9.7% high. The map puts 88.6% of Dunn County in the area it calls Central Plain/Northern Highland and 9.7% in Western Highlands, with one smaller area beside them. USGS gives the first a radon index of 10, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Dunn County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Central Plain/Northern HighlandPre-Late Wisconsinan glacial deposits derived from sandstone and carbonate rocks.Moderate1088.6%
Western HighlandsGlacial deposits derived largely from Ordovician carbonate rocks.High129.7%
Driftless AreaCambrian sandstone.Moderate101.7%

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

Dunn County beside the ground around it

Wisconsin as a whole has more high-potential ground than Dunn County: 34.8% of its land, against 9.7% here. Of the 7 counties that border it, 4 have more high-potential ground, Pierce County the most at 100%.

Share of land by USGS radon potential: Dunn County, the 7 counties bordering it and Wisconsin
AreaEPA zoneLow potentialModerate potentialHigh potential
Dunn CountyZone 2None90.3%9.7%
St. Croix CountyZone 1None0.3%99.7%
Chippewa CountyZone 2None100%None
Pepin CountyZone 1None44.8%55.2%
Pierce CountyZone 1NoneNone100%
Barron CountyZone 2None100%None
Eau Claire CountyZone 2None100%None
Polk CountyZone 2None86.6%13.4%
Wisconsin72 counties, pooled by land areaVaries1.4%63.5%34.8%

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

Local help

Dunn County, Local resources

Radon testing and mitigation in Dunn County

What Wisconsin's program says
Phone
1-888-569-7236
Email
DHSRadon@dhs.wisconsin.gov
Licensing of radon professionals
The State of Wisconsin does not require contractors performing radon measurement or mitigation work to be state licensed or nationally certified.

What it means

Dunn County, Questions

Questions about radon in Dunn County

Are radon levels high in Dunn County?

In 2023, 37.4% of the radon tests reported to CDC for Dunn County, Wisconsin were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.9 pCi/L. Of 69 Wisconsin counties with 30 or more tests for the same period, 35 reported a higher share; pooled, the state comes to 35.7%.

Which counties border Dunn County?

Dunn County borders 7 counties: St. Croix County, Chippewa County, Pepin County, Pierce County, Barron County, Eau Claire County and Polk County.

Products

Dunn County, Products

Testing a home in Dunn County

In Dunn County, 37.4% of 171 tests reported to CDC in 2023 reached 4 pCi/L, against 35.7% pooled across Wisconsin. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Dunn County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Dunn County homes, compared

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Dunn County, Bordering counties

Counties bordering Dunn County

Calculated by Radon411

Dunn County, Cities and towns

Cities and towns in Dunn County

The Census Bureau estimates 46,223 residents in Dunn County for July 1, 2025, 761 more than in 2020 (+1.7%). That works out to 54 people per square mile of land. Its largest town, Menomonie, has 16,664 residents, 36.1% of the total. Together its 8 incorporated places hold 46.1% of those residents; the other 53.9% live outside any of them. CDC's 171 reported tests for 2023 work out to 3.7 per 1,000 residents (2025 estimate), close to Wisconsin's 3.5.

From Menomonie to Downing, CDC publishes no figure by town: each reads Dunn County's.

The cities and towns in Dunn County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Menomonie16,664−1.1%36.1%
Colfax1,193+1.9%2.6%
Elk Mound1,084+9.9%2.3%
Boyceville1,077−0.7%2.3%
Knapp485+1.0%1.0%
Wheeler327−0.6%0.7%
Ridgeland262+0.4%0.6%
Downing225−2.6%0.5%

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).

Dunn County, Homes

Homes in Dunn County

Of Dunn County's 18,812 homes, 65% are detached houses, against 66% across Wisconsin; 14% are in buildings of five or more homes. Half of its homes were built before 1982, close to Wisconsin's 1975: 27% date from before 1960 and 24% from 2000 or later. 67% of occupied homes are lived in by their owner (Wisconsin: 68%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Dunn County, Wisconsin, 2019 to 2023
HomesDunn CountyWisconsin
Housing units18,8122,750,750
Detached houses65%66%
In buildings of 5 or more14%17%
Mobile homes8%3%
Built before 196027%34%
Built since 200024%20%
Middle year built19821975
Owner-occupied67%68%

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