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Radon in Appleton, Wisconsin

Appleton lies in 3 counties, in EPA Zone 2; 85.2% of it is in Outagamie County, where 40.7% of 337 reported tests (2023) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so the only way to know your home's level is to test it.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    40.7%

    5.0 pts above WI

    Outagamie
    40.7%
    Wisconsin
    35.7%

    Outagamie, 30th of 69 in WI, 2023

  • Median result

    3.1pCi/L

    Below action level

    Outagamie
    3.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of Outagamie's tests, 2023

  • Highest county

    51.6%

    Calumet

    Calumet
    51.6%
    Outagamie
    40.7%

    3 counties, 3 with 30+ tests, 2023

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    Outagamie; Calumet Zone 2, Winnebago Zone 2

  • Tests reported

    337

    In Outagamie

    Outagamie
    337
    Winnebago
    512

    Reported to CDC before any fix, 2023

Read a result for Appleton

Starts at Outagamie County's median, 3.1 pCi/L

3.1pCi/L

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

EPA’s reading of 3.1 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. Outagamie County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Appleton, What is published

What is published for Appleton

Information:

Every figure for Appleton is a county's

Radon data is published by county, not by city, and Appleton reaches into 3 counties: Outagamie County, Calumet County and Winnebago County. Each has its own EPA zone and its own CDC test figures, set side by side below and each labelled with its county. Only a test tells you about one home.

Appleton covers 24.8 square miles of land across 3 counties: 85.2% in Outagamie County, 13.1% in Calumet County and 1.7% in Winnebago County. About 75,452 people live there, 3,044 to the square mile.

Appleton, Counties

Appleton's counties, side by side

Measured

Each county's own EPA zone and its own published CDC figures for 2023, the newest period any of them has. A county without a figure for that period is shown without one, never with a figure from another year.

  • Outagamie County
    EPA zone
    Zone 2: Moderate predicted potential
    At or above 4 pCi/L
    40.7%
    Median result
    3.1 pCi/L
    Tests reported
    337 tests
    Annual years on file
    9
  • Calumet County
    EPA zone
    Zone 2: Moderate predicted potential
    At or above 4 pCi/L
    51.6%
    Median result
    4.4 pCi/L
    Tests reported
    122 tests
    Annual years on file
    9
  • Winnebago County
    EPA zone
    Zone 2: Moderate predicted potential
    At or above 4 pCi/L
    42.4%
    Median result
    3.1 pCi/L
    Tests reported
    512 tests
    Annual years on file
    9
The counties Appleton lies in, each with its own EPA zone and its own published CDC figures for 2023
CountyEPA zoneReported tests at or above 4 pCi/LMedian reported resultTests reportedAnnual years on file
Outagamie CountyZone 2: Moderate predicted potential40.7%3.1 pCi/L337 tests9
Calumet CountyZone 2: Moderate predicted potential51.6%4.4 pCi/L122 tests9
Winnebago CountyZone 2: Moderate predicted potential42.4%3.1 pCi/L512 tests9

Appleton spans 3 counties, each with its own EPA zone and its own CDC figure: Outagamie County (Zone 2, 40.7% of 337 tests), Calumet County (Zone 2, 51.6% of 122 tests) and Winnebago County (Zone 2, 42.4% of 512 tests).

Outagamie County ranks 30th of 69 Wisconsin counties with 30 or more tests for that period, 5.0 points above the 35.7% pooled across Wisconsin's counties, 7.3 points above the national pool of 33.4%. Of the city's other counties, Calumet County reported 51.6% and Winnebago County reported 42.4%.

The counties nearest Appleton with a CDC figure for 2023, measured from the middle of the city: Brown County (23 miles, 23.0% of 551 tests), Manitowoc County (31 miles, 31.1% of 209 tests) and Waupaca County (31 miles, 52.8% of 127 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 19.6% to 57.0%; the farthest of them, Sheboygan County, is 44 miles away at 42.9%.

No business in the directory gives Appleton as its address; the Wisconsin list covers it. Wisconsin's other cities with a page of their own: Madison, Green Bay, Oshkosh and Wausau.

Against Wisconsin and its other counties

Radon test figures for the counties Appleton lies in
CountyShare of AppletonTestsAt or above 4 pCi/LMedianWisconsin, pooledRank in the stateEPA zone
Outagamie County85.2%33740.7%3.1 pCi/L35.7%30 of 69Zone 2
Calumet County13.1%12251.6%4.4 pCi/L35.7%11 of 69Zone 2
Winnebago County1.7%51242.4%3.1 pCi/L35.7%25 of 69Zone 2

Shares of tests people chose to run and report, by county (2023); the state's is its counties' counts added up, calculated by Radon411. Only a test measures a home.

The counties around Appleton

By distance from the middle of Appleton; counties with 30 or more tests.

Nearest counties to Appleton with 30 or more tests
CountyDistanceTestsAt or above 4 pCi/LMedian
Brown County23 mi55123.0%1.4 pCi/L
Manitowoc County31 mi20931.1%2.2 pCi/L
Waupaca County31 mi12752.8%4.3 pCi/L
Fond du Lac County37 mi98419.6%1.4 pCi/L
Shawano County40 mi11457.0%5.0 pCi/L
Kewaunee County42 mi5644.6%3.7 pCi/L
Waushara County44 mi7125.4%1.9 pCi/L
Sheboygan County44 mi39942.9%3.3 pCi/L

The median reported pre-mitigation result for 2023 was 3.1 pCi/L in Outagamie County, 4.4 pCi/L in Calumet County and 3.1 pCi/L in Winnebago County.

Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2023.

Appleton, Geology

The ground under Appleton

Predicted

USGS's geologic map puts all of Appleton's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Green Bay Lobe, to which USGS gives a radon index of 10, in the moderate band (9 to 11).

USGS's geologic areas under Appleton
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Green Bay LobeGlacial deposits derived from carbonate and igneous rocks.Moderate10100%

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

Appleton beside its counties and Wisconsin

All of Appleton, like all of Outagamie County, is rated moderate. Across Wisconsin 34.8% of the land is rated high; none of Appleton's is.

Share of land by USGS radon potential: Appleton, the counties it lies in and Wisconsin
AreaEPA zoneLow potentialModerate potentialHigh potential
AppletonBy countyNone100%None
Outagamie CountyZone 2None100%None
Calumet CountyZone 2None72.2%27.8%
Winnebago CountyZone 2None81.5%18.5%
Wisconsin72 counties, pooled by land areaVaries1.4%63.5%34.8%

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

Appleton, Homes

Homes in Appleton

Of Appleton's 31,999 homes, 67% are detached houses, against 71% across Outagamie County; 17% are in buildings of five or more homes. The homes are older than Outagamie County's as a whole: half were built before 1971 (1979 for Outagamie County), and 39% date from before 1960. 67% of occupied homes are lived in by their owner (Outagamie County: 72%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Appleton, Outagamie County, Wisconsin, 2019 to 2023
HomesAppletonOutagamie CountyWisconsin
Housing units31,99979,9002,750,750
Detached houses67%71%66%
In buildings of 5 or more17%15%17%
Mobile homesunder 1%1%3%
Built before 196039%29%34%
Built since 200013%23%20%
Middle year built197119791975
Owner-occupied67%72%68%

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

Local help

Appleton, Local resources

Local resources for Appleton

Who to ask in Wisconsin: its radon program, test kits and professionals.

The program's own words on licensing are on the Wisconsin page.

What it means

Appleton, Questions

Questions about radon in Appleton

What radon zone is Appleton in?

All 3 counties Appleton reaches into (Outagamie County, Calumet County and Winnebago County) are in Zone 2, the map's middle class: a predicted county average of 2 to 4 pCi/L. EPA zones counties, not cities, so that is the zone for every part of Appleton.

What are radon levels in Appleton?

40.7% of the 337 tests reported from Outagamie County for 2023 were at or above 4 pCi/L, the level at which EPA says to fix a home: high results are ordinary around Appleton. The median reported result was 3.1 pCi/L. Calumet County reported 51.6% of 122 tests and Winnebago County reported 42.4% of 512 tests; the counties are kept apart.

Should I test my home in Appleton?

Yes. About 137 of the 337 tests reported from Outagamie County were at or above 4 pCi/L. That is above Wisconsin's pooled 35.7%, and ranks Outagamie County 30th of the 69 Wisconsin counties with 30 or more tests. No map says which homes those are. How to test a home.

What ground is Appleton built on, as far as radon goes?

USGS's geologic map puts all of Appleton on one named area, "Green Bay Lobe", rated moderate for radon potential, radon index 10.

Is radon higher in the counties around Appleton?

Some are and some are not. Against Outagamie County's 40.7%, 4 of the 8 nearest counties with a figure report more and 4 less, from Fond du Lac County (19.6%, 37 miles off) to Shawano County (57.0%, 40 miles off).

The answers use the published figures of Outagamie County, Calumet County and Winnebago County, the counties Appleton lies in.

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