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Radon Levels, Testing and Mitigation in Wisconsin

Wisconsin has 70 counties, with 26 classified as EPA Zone 1 (highest risk). With an average radon level of 7.93 pCi/L, Wisconsin state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.

Wisconsin is the 23rd most expansive state in terms of size and the 20th most populous.

Wisconsin does have an active radon program, dedicated to educating citizens about the risks associated with the deadly gas. You can find more information on Radon, testing and mitigation at the official page.

7.93
Avg. pCi/L
70
Counties
26
Zone 1 Counties

Wisconsin Radon Map

Wisconsin radon levels by county
Zone 1 — High
Zone 2 — Moderate
Zone 3 — Low

Wisconsin Metro Areas

Explore radon data organized by metro region, including average levels, hotspot cities, and local mitigation professionals.

Appleton Metro
5 cities
Duluth Metro
5 cities
Eau Claire Metro
5 cities
Green Bay Metro
5 cities
Janesville Metro
5 cities
Kenosha Metro
5 cities
La Crosse Metro
5 cities
Madison Metro
5 cities
Milwaukee Metro
5 cities
Minneapolis-St. Paul Metro
5 cities
Oshkosh Metro
5 cities
Racine Metro
5 cities

Most Active Radon Markets in Wisconsin

Cities with the most user-submitted radon test data, ranked by number of submissions.

CityAvg User Radon LevelSubmissions
Milwaukee 10.00 pCi/L 3
Prairie Du Chien 10.00 pCi/L 2
Stevens Point 5.50 pCi/L 2
Menomonie 10.00 pCi/L 1
Delavan 6.00 pCi/L 1
Shawano No submissions 0
Sturgeon Bay No submissions 0

Wisconsin Counties by EPA Radon Zone

All 70 Wisconsin counties with their EPA radon zone classification and user-submitted average radon levels.

Zone 1 — High Risk
Predicted avg. indoor levels > 4.0 pCi/L
Zone 1 26 counties
Buffalo County Zone 1
Avg:
Crawford County Zone 1
Avg: 10.0 pCi/L
Dane County Zone 1
Avg: 9.8 pCi/L
Dodge County Zone 1
Avg: 7.0 pCi/L
Door County Zone 1
Avg: 5.0 pCi/L
Fond du Lac County Zone 1
Avg:
Grant County Zone 1
Avg: 17.0 pCi/L
Green County Zone 1
Avg: 11.0 pCi/L
Green Lake County Zone 1
Avg: 6.0 pCi/L
Iowa County Zone 1
Avg: 8.0 pCi/L
Jefferson County Zone 1
Avg: 7.0 pCi/L
Lafayette County Zone 1
Avg:
Langlade County Zone 1
Avg: 11.3 pCi/L
Marathon County Zone 1
Avg: 9.5 pCi/L
Pepin County Zone 1
Avg:
Pierce County Zone 1
Avg: 6.3 pCi/L
Portage County Zone 1
Avg: 5.5 pCi/L
Richland County Zone 1
Avg: 6.0 pCi/L
Rock County Zone 1
Avg: 11.5 pCi/L
Shawano County Zone 1
Avg: 8.0 pCi/L
Vernon County Zone 1
Avg: 5.0 pCi/L
Walworth County Zone 1
Avg: 6.7 pCi/L
Washington County Zone 1
Avg: 12.0 pCi/L
Waukesha County Zone 1
Avg: 6.8 pCi/L
Waupaca County Zone 1
Avg:
Wood County Zone 1
Avg: 9.0 pCi/L
Zone 2 — Moderate Risk
Predicted avg. indoor levels 2–4 pCi/L
Zone 2 44 counties
Adams County Zone 2
Avg: 13.0 pCi/L
Ashland County Zone 2
Avg: 8.7 pCi/L
Barron County Zone 2
Avg: 5.0 pCi/L
Bayfield County Zone 2
Avg: 7.0 pCi/L
Brown County Zone 2
Avg: 4.0 pCi/L
Burnett County Zone 2
Avg: 4.0 pCi/L
Calumet County Zone 2
Avg: 7.0 pCi/L
Chippewa County Zone 2
Avg: 4.7 pCi/L
Clark County Zone 2
Avg:
Columbia County Zone 2
Avg: 7.3 pCi/L
Douglas County Zone 2
Avg:
Dunn County Zone 2
Avg:
Eau Claire County Zone 2
Avg: 7.0 pCi/L
Florence County Zone 2
Avg: 6.0 pCi/L
Forest County Zone 2
Avg: 7.0 pCi/L
Iron County Zone 2
Avg:
Jackson County Zone 2
Avg: 9.0 pCi/L
Juneau County Zone 2
Avg: 7.5 pCi/L
Kenosha County Zone 2
Avg:
Kewaunee County Zone 2
Avg: 5.0 pCi/L
La Crosse County Zone 2
Avg: 2.5 pCi/L
Lincoln County Zone 2
Avg: 4.0 pCi/L
Manitowoc County Zone 2
Avg:
Marinette County Zone 2
Avg: 15.0 pCi/L
Marquette County Zone 2
Avg:
Milwaukee County Zone 2
Avg: 8.7 pCi/L
Monroe County Zone 2
Avg: 6.3 pCi/L
Oconto County Zone 2
Avg: 16.0 pCi/L
Oneida County Zone 2
Avg: 7.0 pCi/L
Outagamie County Zone 2
Avg: 7.0 pCi/L
Ozaukee County Zone 2
Avg: 8.5 pCi/L
Polk County Zone 2
Avg: 5.0 pCi/L
Price County Zone 2
Avg:
Racine County Zone 2
Avg: 8.3 pCi/L
Rusk County Zone 2
Avg: 11.5 pCi/L
Sauk County Zone 2
Avg: 6.8 pCi/L
Sawyer County Zone 2
Avg: 5.0 pCi/L
Sheboygan County Zone 2
Avg: 5.5 pCi/L
Taylor County Zone 2
Avg: 7.5 pCi/L
Trempealeau County Zone 2
Avg: 5.0 pCi/L
Vilas County Zone 2
Avg: 7.7 pCi/L
Washburn County Zone 2
Avg: 5.7 pCi/L
Waushara County Zone 2
Avg: 12.3 pCi/L
Winnebago County Zone 2
Avg: 19.0 pCi/L

Wisconsin Cities & Towns

Browse radon data for individual cities across Wisconsin. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.

Abbotsford Abrams Adams Adell Albany Algoma Allenton Alma Alma Center Almena Almond Altoona Amberg Amery Amherst Amherst Junction Aniwa Antigo Appleton Arcadia Arena Argonne Argyle Arkansaw Arkdale Arlington Armstrong Creek Arpin Ashland Athelstane Athens Auburndale Augusta Avalon Avoca Bagley Baileys Harbor Baldwin Balsam Lake Bancroft Bangor Baraboo Barneveld Barron Barronett Bay City Bayfield Bear Creek Beaver Dam Beldenville Belgium Belleville Belmont Beloit Benton Berlin Big Bend Birchwood Birnamwood Black Creek Black Earth Black River Falls Blair Blanchardville Bloomer Bloomington Blue Mounds Blue River Bonduel Boscobel Boulder Junction Bowler Boyceville Boyd Brandon Brantwood Briggsville Brillion Bristol Brodhead Brookfield Brooklyn Brownsville Browntown Bruce Brule Brussels Bryant Burlington Burnett Butler Butternut Cable Cadott Caledonia Cambria Cambridge Cameron Camp Douglas Campbellsport Caroline Cascade Casco Cashton Cassville Catawba Cazenovia Cecil Cedar Grove Cedarburg Centuria Chaseburg Chetek Chili Chilton Chippewa Falls Clam Lake Clayton Clear Lake Cleveland Clinton Clintonville Cobb Cochrane Colby Coleman Colfax Colgate Coloma Columbus Combined Locks Comstock Conover Conrath Coon Valley Cornell Cornucopia Cottage Grove Couderay Crandon Crivitz Cross Plains Cuba City Cudahy Cumberland Curtiss Cushing Custer Dallas Dalton Danbury Dane Darien Darlington De Forest De Pere De Soto Deer Park Deerbrook Deerfield Delafield Delavan Denmark Dodge Dodgeville Dorchester Dousman Downing Dresser Drummond Dunbar Durand Eagle Eagle River East Troy Eastman Eau Claire Eau Galle Eden Edgar Edgerton Egg Harbor Eland Elcho Eldorado Eleva Elk Mound Elkhart Lake Elkhorn Ellison Bay Ellsworth Elm Grove Elmwood Elroy Elton Endeavor Ettrick Evansville Exeland Fairchild Fall Creek Fall River Fence Fennimore Ferryville Fifield Fish Creek Florence Fond Du Lac Fontana Forest Junction Forestville Fort Atkinson Fountain City Fox Lake Foxboro Franklin Franksville Frederic Fredonia Fremont Friendship Galesville Gays Mills Genoa Genoa City Germantown Gile Gillett Gilman Gleason Glen Flora Glen Haven Glenbeulah Glenwood City Glidden Goodman Gordon Grafton Grand Marsh Grand View Granton Grantsburg Gratiot Green Bay Green Lake Green Valley Greendale Greenleaf Greenville Greenwood Gresham Hager City Hales Corners Hammond Hancock Harshaw Hartford Hartland Hatley Haugen Hawkins Hayward Hazel Green Hazelhurst Helenville Herbster Hertel Hewitt High Bridge Highland Hilbert Hillpoint Hillsboro Hixton Holcombe Hollandale Holmen Horicon Hortonville Houlton Hubertus Hudson Humbird Hurley Hustisford Independence Iola Irma Iron Ridge Iron River Ixonia Jackson Janesville Jefferson Jim Falls Johnson Creek Juda Junction City Juneau Kansasville Kaukauna Kendall Kennan Kenosha Keshena Kewaskum Kewaunee Kiel Kimberly Knapp Kohler Krakow La Crosse La Farge La Valle Lac Du Flambeau Ladysmith Lake Geneva Lake Mills Lake Nebagamon Lake Tomahawk Lakewood Lancaster Land O Lakes Lannon Laona Larsen Lena Leopolis Linden Little Chute Little Suamico Livingston Lodi Loganville Lomira Lone Rock Long Lake Lowell Loyal Lublin Luck Luxemburg Lyndon Station Madison Maiden Rock Malone Manawa Manitowish Waters Manitowoc Maple Marathon Marengo Maribel Marinette Marion Markesan Marshall Marshfield Mason Mauston Mayville Mazomanie Mc Farland Medford Mellen Melrose Menasha Menomonee Falls Menomonie Mequon Mercer Merrill Merrillan Merrimac Middleton Milladore Milltown Milton Milwaukee Mindoro Mineral Point Minocqua Minong Mishicot Mondovi Monroe Montello Montfort Monticello Montreal Mosinee Mount Calvary Mount Hope Mount Horeb Mountain Mukwonago Muscoda Muskego Nashotah Necedah Neenah Neillsville Nekoosa Nelson Neopit Neosho Neshkoro New Auburn New Berlin New Franken New Glarus New Holstein New Lisbon New London New Richmond Newton Niagara North Freedom North Prairie Norwalk Oak Creek Oakfield Oconomowoc Oconto Oconto Falls Ogdensburg Ogema Ojibwa Okauchee Omro Onalaska Oneida Ontario Oostburg Oregon Orfordville Osceola Oshkosh Osseo Owen Oxford Palmyra Pardeeville Park Falls Pearson Pelican Lake Pembine Pepin Peshtigo Pewaukee Phelps Phillips Pickerel Pickett Pine River Pittsville Plain Plainfield Platteville Pleasant Prairie Plover Plum City Plymouth Poplar Port Edwards Port Washington Port Wing Portage Porterfield Potosi Pound Poy Sippi Poynette Prairie Du Chien Prairie Du Sac Prairie Farm Prentice Prescott Presque Isle Princeton Pulaski Racine Radisson Randolph Random Lake Readstown Redgranite Reedsburg Reedsville Reeseville Rewey Rhinelander Rib Lake Rice Lake Richfield Richland Center Ridgeland Ridgeway Ringle Rio Ripon River Falls Roberts Rock Springs Rockland Rosendale Rosholt Rothschild Rubicon Rudolph Saint Cloud Saint Croix Falls Saint Francis Saint Germain Salem Sarona Sauk City Saukville Saxon Sayner Scandinavia Schofield Seymour Sharon Shawano Sheboygan Sheboygan Falls Sheldon Shell Lake Sherwood Shiocton Shullsburg Silver Lake Siren Sister Bay Slinger Sobieski Soldiers Grove Solon Springs Somerset South Milwaukee South Range South Wayne Sparta Spencer Spooner Spring Green Spring Valley Springbrook Stanley Star Lake Star Prairie Stetsonville Steuben Stevens Point Stitzer Stockholm Stoddard Stone Lake Stoughton Stratford Strum Sturgeon Bay Sturtevant Suamico Sullivan Summit Lake Sun Prairie Superior Suring Sussex Taylor Theresa Thiensville Thorp Three Lakes Tigerton Tilleda Tomah Tomahawk Tony Townsend Trego Trempealeau Trevor Tripoli Turtle Lake Twin Lakes Two Rivers Union Grove Unity Upson Valders Van Dyne Verona Vesper Viola Viroqua Wabeno Waldo Wales Walworth Warrens Washburn Washington Island Waterford Waterloo Watertown Waukesha Waunakee Waupaca Waupun Wausau Wausaukee Wautoma Wauzeka Webster West Bend West Salem Westboro Westby Westfield Weyauwega Weyerhaeuser Wheeler White Lake Whitehall Whitelaw Whitewater Wild Rose Willard Williams Bay Wilson Wilton Windsor Winneconne Winter Wisconsin Dells Wisconsin Rapids Withee Wittenberg Wonewoc Woodland Woodman Woodruff Woodville Wrightstown

Frequently Asked Questions About Radon in Wisconsin

What radon level is considered "high"?
The EPA action level is 4.0 pCi/L — many homeowners also choose to fix levels between 2.0 and 4.0 pCi/L. Any home with levels at or above 4.0 pCi/L should be mitigated.
How much does radon mitigation cost in Wisconsin?
Radon mitigation typically costs between $800 and $2,500, depending on foundation type and radon severity. A standard sub-slab depressurization system usually falls in the $1,000–$1,500 range.
Does mitigation actually work?
Yes — properly installed systems typically reduce radon levels by up to 99%. A post-mitigation test confirms the system is working correctly, and many homeowners re-test periodically.
Should I test again after mitigation?
Yes. A post-mitigation test is the proof your system is working. The EPA recommends testing within 30 days of installation and retesting every two years.
What EPA Radon Zone is my Wisconsin county in?
Wisconsin counties are classified into three EPA Radon Zones. Zone 1 (highest risk, >4 pCi/L) indicates the most concern. Zone 2 (moderate, 2–4 pCi/L) and Zone 3 (lowest, <2 pCi/L) round out the classification. Use the county directory above to find your specific county's zone and data.

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