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Radon in Menard County, Illinois

Menard County, Illinois, is in EPA radon Zone 1: predicted average indoor radon screening level greater than 4 pCi/L (highest potential). Radon laboratories reported 82 building tests here for 2008 to 2017: median 4.2 pCi/L, with 51.3% at or above EPA's 4 pCi/L action level (Illinois 43.2%, US 36.5%).

Zone 1
EPA radon zone (1993 county map)
4.2
median lab test, pCi/L (2008-2017)
51.3%
of lab tests at or above 4 pCi/L
82
buildings tested by labs, 2008-2017

Radon test results in Menard County

Radon test results on file for Menard County, IL, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-201782median 4.2 pCi/L51.3%
Illinois, all counties (labs)2008-201785,532n/a43.2%
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
Mason County, ILZone 17843.1%
Sangamon County, ILZone 11,92952.2%
Logan County, ILZone 126762.1%
Cass County, ILZone 13338.5%
Morgan County, ILZone 111664.5%
Tazewell County, ILZone 14,05559.6%

The six counties with the nearest centers.

What to do about radon in Menard 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. Illinois'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 Menard County address

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

Radon in Menard County: questions

What is the radon level in Menard County?

The median of the 82 laboratory tests reported for Menard County (2008 to 2017) was 4.2 pCi/L, and 51.3% 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 Menard County in radon Zone 1?

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

How does radon in Menard County compare with Illinois?

51.3% of laboratory tests in Menard County were at or above 4 pCi/L for 2008 to 2017, against 43.2% across Illinois (85,532 tests) and 36.5% nationally. 56 of Illinois's 102 counties are in Zone 1.

Should I test for radon in Menard 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 Menard 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 Illinois county · Radon map of every state

Data compiled 2026-10-20. County FIPS 17129. County-level screening information, not a radon measurement of any building.