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Radon Levels in Adams County, Wisconsin

EPA puts Adams County in Zone 2, its middle radon zone, and 20.8% of its 48 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

    20.8%

    14.9 pts below WI

    Adams
    20.8%
    Wisconsin
    35.7%

    48 tests, 2023

  • Median result

    1.7pCi/L

    Below action level

    Adams
    1.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    48

    61st of 69 by tests

    Adams
    48
    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

    60 of 69

    Lowest quarter

    Adams
    20.8%
    Langlade
    65.8%

    By share, of 69 with 30+ tests

Read a result for Adams County

Starts at Adams County's median, 1.7 pCi/L

1.7pCi/L

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

EPA’s reading of 1.7 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Adams County's median reported result, 2023.

Interpret this reading

The data

Adams County, At a glance

Adams County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Adams 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Adams County, 2023

Share of reported tests at or above 4 pCi/L, by year, Adams County
Share of reported tests at or above 4 pCi/L, by year, Adams County
YearShare of reported tests at or above 4 pCi/L
201427.3%
201521.1%
201622.7%
201713.5%
201912.3%
202017.9%
202119.0%
20222.7%
202320.8%

2023: 20.8%. Across these years the share ran from 2.7% to 27.3%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 48 tests reported to CDC for Adams 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

Adams County, Compared

Adams County radon figures, compared

Calculated by Radon411

Adams County's 48 reported tests in 2023 had a middle value of 1.7 pCi/L and a maximum of 19.8 pCi/L, and 20.8% reached 4 pCi/L. Wisconsin as a whole (72 Wisconsin counties, pooled) comes to 35.7%: 14.9 points higher than here.

Among its state's counties it ranks 60th of 69 Wisconsin counties with 30 or more tests for the same period. Statewide for the same period, Langlade County reported the highest share (65.8%) and Bayfield County the lowest (5.7%).

Below the action level, 31 tests (64.6%) came in under 2 pCi/L, against 41.4% statewide, and 7 tests (14.6%) fell between 2 and 4, against 23.0% statewide. The busiest year on file was 2022, with 259 tests reported; the quietest, 2015, had 19.

EPA's 1993 zone map puts Adams County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Next door, the shares run from 10.0% in Juneau County to 41.1% in Sauk County, with Wood County, Marquette County and Juneau County below Adams County. Over 6 years of annual figures the share fell 6.5 points, from 27.3% in 2014 to 20.8% in 2023; its peak was 27.3% in 2014.

Share of reported tests at or above 4 pCi/L by year, Adams County against Wisconsin2014 to 2023, years with 30 or more tests: Adams County 27.3% to 20.8%, the state's pooled share 35.7% in 2023.
Adams CountyWisconsin, pooled
Share of reported tests at or above 4 pCi/L by year, Adams County against Wisconsin: data table
YearTestsAdams County, at or above 4 pCi/LWisconsin, pooled
20143327.3%51.1%
20173713.5%44.8%
20196512.3%42.9%
20203917.9%27.0%
20222592.7%42.9%
20234820.8%35.7%
Adams County against Wisconsin, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Adams County
Adams County4820.8%1.7 pCi/LThis county
Wisconsin, pooled72 counties, pooled20,87935.7%Not pooled+14.9 points
United States, pooled642 counties, pooled128,74033.4%Not pooled+12.6 points
Langlade Countyhighest in the state22565.8%6.0 pCi/L+45.0 points
Bayfield Countylowest in the state355.7%1.5 pCi/L−15.1 points
Sauk County, WIborders it24141.1%3.3 pCi/L+20.3 points
Portage County, WIborders it33435.6%3.0 pCi/L+14.8 points
Columbia County, WIborders it16328.8%2.0 pCi/L+8.0 points
Waushara County, WIborders it7125.4%1.9 pCi/L+4.6 points
Wood County, WIborders it20818.3%1.4 pCi/L−2.5 points
Marquette County, WIborders it4015.0%1.3 pCi/L−5.8 points
Juneau County, WIborders it5010.0%1.1 pCi/L−10.8 points
Where Adams County's reported results fell, 2023, beside Wisconsin and the United States
ResultAdams County testsAdams County shareWisconsin shareU.S. shareAgainst Wisconsin
Under 2 pCi/L3164.6%41.4%41.4%+23.2 points
2 to 4 pCi/L714.6%23.0%25.2%−8.4 points
4 pCi/L and above1020.8%35.7%33.4%−14.9 points
Adams 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
Lincoln County55 of 698123.5%2.1 pCi/L
Burnett County56 of 695223.1%1.6 pCi/L
Brown County57 of 6955123.0%1.4 pCi/L
Monroe County58 of 6921322.5%2.2 pCi/L
Vilas County59 of 6910621.7%2.1 pCi/L
Adams County60 of 694820.8%1.7 pCi/L
Milwaukee County61 of 692,60520.2%1.5 pCi/L
Fond du Lac County62 of 6998419.6%1.4 pCi/L
Taylor County63 of 693718.9%2.1 pCi/L
Wood County64 of 6920818.3%1.4 pCi/L
Pepin County65 of 696515.4%1.2 pCi/L
Adams County radon tests by year, against Wisconsin's pooled share
YearTestsAt or above 4 pCi/LMedianHighestWisconsin, pooledChange from the row before
20234820.8%1.7 pCi/L19.8 pCi/L35.7%+18.1 points
20222592.7%0.8 pCi/L8.0 pCi/L42.9%−16.3 points
20212119.0%1.4 pCi/L6.9 pCi/L39.9%+1.1 points
20203917.9%1.9 pCi/L8.1 pCi/L27.0%+5.6 points
20196512.3%1.3 pCi/L18.6 pCi/L42.9%−1.2 points
20173713.5%1.5 pCi/L7.2 pCi/L44.8%−9.2 points
20162222.7%1.7 pCi/L12.7 pCi/L45.2%+1.6 points
20151921.1%2.4 pCi/L8.1 pCi/L51.6%−6.2 points
20143327.3%2.7 pCi/L13.1 pCi/L51.1%First on file

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

Adams County, Geology

The ground under Adams County

Predicted

USGS's geologic map puts all of Adams County's mapped land in one class: moderate radon potential. The map puts 66.3% of Adams County in the area it calls Driftless Area and 19.3% in Central Plain/Northern Highland, with one smaller area beside them. USGS gives both a radon index of 10, in the moderate band (9 to 11).

USGS's geologic areas under Adams County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Driftless AreaCambrian sandstone.Moderate1066.3%
Central Plain/Northern HighlandPre-Late Wisconsinan glacial deposits derived from sandstone and carbonate rocks.Moderate1019.3%
Green Bay LobeGlacial deposits derived from carbonate and igneous rocks.Moderate1014.3%

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

Adams County beside the ground around it

Across Wisconsin 34.8% of the land is rated high; none of Adams County's is. Of the 7 counties that border it, 4 have more high-potential ground, Portage County the most at 76.0%.

Share of land by USGS radon potential: Adams County, the 7 counties bordering it and Wisconsin
AreaEPA zoneLow potentialModerate potentialHigh potential
Adams CountyZone 2None100%None
Juneau CountyZone 2None100%None
Marquette CountyZone 2None100%None
Waushara CountyZone 2None100%None
Portage CountyZone 1None24.0%76.0%
Sauk CountyZone 2None99.9%0.1%
Wood CountyZone 1None46.3%53.7%
Columbia CountyZone 2None64.1%35.9%
Wisconsin72 counties, pooled by land areaVaries1.4%63.5%34.8%

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

Local help

Adams County, Local resources

Radon testing and mitigation in Adams 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

Adams County, Questions

Questions about radon in Adams County

Are radon levels high in Adams County?

In 2023, 20.8% of the radon tests reported to CDC for Adams County, Wisconsin were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.7 pCi/L. Of 69 Wisconsin counties with 30 or more tests for the same period, 59 reported a higher share; pooled, the state comes to 35.7%.

Which counties border Adams County?

Adams County borders 7 counties: Juneau County, Marquette County, Waushara County, Portage County, Sauk County, Wood County and Columbia County.

Products

Adams County, Products

Testing a home in Adams County

In Adams County, 20.8% of 48 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 Adams County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Adams County homes, compared

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Adams County, Bordering counties

Counties bordering Adams County

Calculated by Radon411

Adams County, Cities and towns

Cities and towns in Adams County

Adams County is growing: the Census Bureau puts it at 21,752 residents on July 1, 2025, up 5.1% from 20,687 in 2020. That works out to 34 people per square mile of land. Wisconsin Dells, the largest place on its list (3,149 residents in all), extends beyond Adams County, so no share of the total is worked out for it. Reported testing is thin here: 48 tests over 2023, or 2.2 for every 1,000 residents (2025 estimate), where Wisconsin as a whole comes to 3.5.

From Wisconsin Dells to Friendship, CDC publishes no figure by town: each reads Adams County's.

The cities and towns in Adams County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Wisconsin Dellsextends beyond Adams County3,149+4.5%Counted whole
Adams1,803+2.2%8.3%
Friendship683+6.1%3.1%

3 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 Adams County is counted whole, so it has no share.

Adams County, Homes

Homes in Adams County

Of Adams County's 16,873 homes, 74% are detached houses, against 66% across Wisconsin; 19% are mobile homes. Much of Adams County is recent building: 23% of its homes have gone up since 2000 and the middle year built is 1983, against 1975 for Wisconsin. Owners live in 86% of the occupied homes (Wisconsin: 68%), so for most households a test and a fix are their own to order.

Homes in Adams County, Wisconsin, 2019 to 2023
HomesAdams CountyWisconsin
Housing units16,8732,750,750
Detached houses74%66%
In buildings of 5 or more4%17%
Mobile homes19%3%
Built before 196014%34%
Built since 200023%20%
Middle year built19831975
Owner-occupied86%68%

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