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Illinois Radon Map and Levels by County

Illinois's counties span all three EPA radon zones. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

Predicted
56 of 102counties in Zone 1, EPA's highest radon zone
Measured
By countyCDC publishes Illinois's test figures by county: 102 of 102 counties have one.
Your home
Test to knowNo area figure here is a reading of your home.
How to test this homeFind a certified tester

The data

Illinois, At a glance

Illinois at a glance

Predicted: EPA radon zone

102 of 102 counties classified

EPA classifies counties, not states. Of the 102 counties in Illinois with a zone, 56 are in Zone 1, 43 in Zone 2 and 3 in Zone 3.

  • Zone 1: Highest predicted potentialgreater than 4 pCi/L56 of 102 counties · 54.9%
  • Zone 2: Moderate predicted potential2 to 4 pCi/L43 of 102 counties · 42.2%
  • Zone 3: Lower predicted potentialless than 2 pCi/L3 of 102 counties · 2.9%

An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC test figures, county by county

CDC publishes Illinois's radon test figures by county: 102 of its 102 counties have one. Each one's share is in the county list.

Illinois, Counties

Illinois counties by EPA zone

Predicted

Illinois's radon map, then all 102 counties by the zone EPA predicts for each, highest reported share of tests at or above 4 pCi/L first. Each has its own report.

Illinois radon map by county: EPA radon zones. Map of Illinois's 102 counties shaded by EPA radon zone: Zone 1 in red-orange, Zone 2 in amber, Zone 3 in pale sand. 56 in Zone 1, 43 in Zone 2, 3 in Zone 3.
Illinois radon map by countyEPA radon zones for Illinois's counties: 56 counties in Zone 1, 43 counties in Zone 2, 3 counties in Zone 3.Predicted potential for each county, not a reading of any home. Homes with elevated levels of radon have been found in all three zones.

Zone 1: highest predicted potential56

Local help

Illinois, Local resources

Local resources in Illinois

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

What Illinois's program says
Phone
(800) 325-1245
Licensing of radon professionals
The Agency also licenses and regulates the individuals who provide radon measurement and mitigation to the public.
Disclosure when a home is sold or rented
Illinois Radon Awareness Act - This is the legislation that requires the seller to provide to the buyer of any interest in residential real property the IEMA-OHS pamphlet entitled "Radon Testing Guidelines for Real Estate Transactions" and the Illinois Disclosure of Information on Radon Hazards.

Radon Action Brief

National Radon Action MonthPre-sale

The radon brief for your Illinois county, in one dated file.

  • Your area's radon record, explained.
  • Your plan to test this week.
  • Fix costs and pros near you.

Save 64%Sale price: $8.99Price after the sale: $25Ends Jan 31Then $25

Get your Illinois county's BriefSee a free sample

Area data, not a test of the building.

What it means

Illinois, Questions

Questions about radon in Illinois

Common questions

9 questions, answered from the figures above

Is radon a problem in Illinois?

EPA's Map of Radon Zones places 56 of the 102 Illinois counties it classifies in Zone 1, the highest predicted potential, 43 in Zone 2 and 3 in Zone 3. An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.

Illinois on the radon mapRadon levels by state

How do I get a radon test in Illinois?

EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. The Illinois radon program is the place to ask about certified testers and any test kit offer it runs.

How to test a homeFree and low-cost kits by stateIllinois radon program

Who does radon mitigation in Illinois?

Radon411's Illinois directory lists 337 radon businesses for testing, mitigation or both, each with the licensing list it was read from. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional.

How radon mitigation worksWhat mitigation costsRadon professionals in Illinois

Which Illinois counties are in EPA radon Zone 1?

56 counties are in Zone 1: Adams County, Boone County, Brown County, Bureau County, Calhoun County, Carroll County, Cass County, Champaign County, and 48 more in the county table on this page. Zone 1 is EPA's class for highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. A zone is a prediction for a county, not a measurement of any home.

Radon in Adams CountyRadon in Boone CountyRadon in Brown County

Which Illinois counties have the highest radon?

102 of Illinois's 102 counties have an EPA radon zone published here. Radon411 will not rank counties on data it does not hold, and a zone is a prediction for an area rather than a measurement of any building.

What share of radon tests in Illinois are high?

CDC has published no statewide radon testing statistics for Illinois, so we cannot give a figure. Where CDC does publish one, the percentage describes radon tests reported to CDC, not homes.

Which EPA region is Illinois in?

Illinois is in EPA Region 5: Great Lakes.

Do I need to test my home in Illinois?

Yes, wherever you live in the state. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L.

Why does this page show coverage rather than one radon level for Illinois?

A statewide figure averages counties with very different geology and very different numbers of reported tests, so it hides more than it shows. The county report is the level at which the EPA zone, the geologic potential and the reported testing statistics are actually published, which is why the county table above links to every one of them.

If you own, buy, sell or rent

What these figures mean for each reader, with the guide that covers it

The zone counts on this page describe counties across Illinois. They are predictions for areas, and none of them measures your building.

Illinois in figures

The figures above, said in words

What the published data says about Illinois, in words. A zone and a share of tests describe an area, never the level in any one home.

    • Predicted

      Predicted

      EPA places 56 of Illinois's 102 counties in Zone 1, 43 in Zone 2 and 3 in Zone 3.

      Zone 1 counties, A to Z, begin with Adams County, Boone County and Brown County; the county section below lists all 56.

    • Compared

      Calculated by Radon411

      55% of Illinois's counties with a zone on file are in Zone 1, a larger share than across all U.S. counties (34%). It is a share of counties, not of land, people or homes.

  • Reported tests

    Measured

    CDC has no statewide testing figure for Illinois on file here.

    102 of the 102 counties have a published county figure; the most tests in each one's latest year were reported for Cook County (26,937 tests in 2017), DuPage County (19,401 tests in 2017) and Lake County (13,050 tests in 2017).

  • Local record

    Illinois's radon program is the IEMA-OHS Radon Program, run by Illinois Emergency Management Agency and Office of Homeland Security; its contacts are under Local resources.

    2 cities have a page setting the figures of the counties it lies in side by side: Rockford and St. Charles.

Products

Illinois, Products

Testing and mitigation products

Whatever the figures for Illinois show, only a test tells you about one home.

Test kits and monitors42

See all products

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Best radon monitors for Illinois homes, compared

Testing

5

Mitigation

3

Explore

Cities in Illinois with their own page

Radon data is published by county, not by city. Each city page sets the figures of the counties the city lies in side by side.

Illinois, Next steps

What to do next

  1. LearnKnow what radon isWhat radon is, how it gets indoors, and why a county zone is not a reading for your home.Learn about radon
  2. TestTest the building you live inShort-term or long-term, where the device goes, and closed-house conditions.How to test
  3. FixBring a high level downHow a mitigation system works, and the retest that confirms it.How mitigation works
  4. Find a proHire a certified professionalMeasurement and mitigation professionals by state, with their certifications.Find a professional

Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.