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Radon in Fond du Lac County, Wisconsin

Fond du Lac County, Wisconsin, is in EPA radon Zone 1: predicted average indoor radon screening level greater than 4 pCi/L (highest potential). Radon laboratories reported 970 building tests here for 2008 to 2017: median 4.6 pCi/L, with 56.4% at or above EPA's 4 pCi/L action level (Wisconsin 47%, US 36.5%).

Zone 1
EPA radon zone (1993 county map)
4.6
median lab test, pCi/L (2008-2017)
56.4%
of lab tests at or above 4 pCi/L
970
buildings tested by labs, 2008-2017

Radon test results in Fond du Lac County

Radon test results on file for Fond du Lac County, WI, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-2017970median 4.6 pCi/L56.4%
Wisconsin radon program2023354median 1.4 pCi/L19.6%
Wisconsin, all counties (labs)2008-201755,359n/a47%
United States (labs)2008-20171,408,802n/a36.5%

Test results describe buildings whose owners chose to test and whose results reached the lab or agency, not a random sample; small counts swing widely. State and US shares are computed from county counts and percents. The laboratory data comes from national radon testing laboratories and supplements EPA's zone map.

Radon in nearby counties

CountyEPA zoneLab tests4 pCi/L or more
Green Lake County, WIZone 112453.6%
Winnebago County, WIZone 21,73756.4%
Dodge County, WIZone 181563.3%
Calumet County, WIZone 233459.8%
Washington County, WIZone 12,34956%
Ozaukee County, WIZone 21,30846.4%

The six counties with the nearest centers.

What to do about radon in Fond du Lac County

Test the building. EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, and says there is no known safe level of exposure. Wisconsin's state radon program can point you to testers and test kits.

Buying here? The Environmental Records Report lists this county's radon zone and test results with the flood zone, mapped faults, power lines and federal contamination records near the address.

Check one Fond du Lac County address

Environmental Records Report, $29. PDF and JSON, usually ready in about a minute.

Radon in Fond du Lac County: questions

What is the radon level in Fond du Lac County?

The median of the 970 laboratory tests reported for Fond du Lac County (2008 to 2017) was 4.6 pCi/L, and 56.4% of them were at or above 4 pCi/L. These are results of tested buildings; a single home can be far above or below them.

Is Fond du Lac County in radon Zone 1?

Yes. EPA's 1993 Map of Radon Zones puts Fond du Lac County in Zone 1, the counties with a predicted average indoor radon screening level above 4 pCi/L.

How does radon in Fond du Lac County compare with Wisconsin?

56.4% of laboratory tests in Fond du Lac County were at or above 4 pCi/L for 2008 to 2017, against 47% across Wisconsin (55,359 tests) and 36.5% nationally. 28 of Wisconsin's 72 counties are in Zone 1.

Should I test for radon in Fond du Lac County?

Yes. EPA recommends testing every home whatever its zone: "This map should not be used to determine if individual homes need to be tested." Fix the home at 4 pCi/L or more and consider a fix between 2 and 4 pCi/L; EPA says there is no known safe level of radon exposure.

More for Fond du Lac County

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Radon in every Wisconsin county · Radon map of every state

Data compiled 2026-10-20. County FIPS 55039. County-level screening information, not a radon measurement of any building.