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Radon Levels in Edgar County, Illinois

EPA puts Edgar County in Zone 1, its highest radon zone, and only 21 radon tests from it are on file with CDC (2017). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    37.9%

    5.2 pts below IL

    Edgar
    37.9%
    Illinois
    43.1%

    116 tests, 2008 to 2017

  • Median result

    3.2pCi/L

    Below action level

    Edgar
    3.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    116

    68th of 93 by tests

    Edgar
    116
    Cook
    14,199

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Illinois

    60 of 93

    Middle half

    Edgar
    37.9%
    Stark
    80.5%

    By share, of 93 with 30+ tests

Read a result for Edgar County

Starts at Edgar County's median, 3.2 pCi/L

3.2pCi/L

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

EPA’s reading of 3.2 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. Edgar County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Edgar County, At a glance

Edgar County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Edgar County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 95% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Edgar County, 2017

Share of reported tests at or above 4 pCi/L, by year, Edgar County
Share of reported tests at or above 4 pCi/L, by year, Edgar County
YearShare of reported tests at or above 4 pCi/L
2014100.0%
201550.0%
201757.1%

2017: 57.1%. Across these years the share ran from 50.0% to 100.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 21 tests were reported to CDC for Edgar County over 2017, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.

Measured: CDC tracking data. Figure above: 2017. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Edgar County, Compared

Edgar County radon figures, compared

Calculated by Radon411

In Edgar County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (44 of 116) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 2.2 points higher. Across 102 Illinois counties pooled together, 43.1% of tests reached that level, so Edgar County runs 5.2 points below its state.

The newest figure, in 2017, counts only 21 tests (57.1% at or above 4 pCi/L), too few to compare, so this reading uses the 116-test figure.

Of 6 neighbours with a figure, 5 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 22.1% (Clark County) to 50.2% (Champaign County). By share, Edgar County is 60th of 93 Illinois counties with 30 or more tests for the same period.

Half the tests came in under 3.2 pCi/L and half over it; the single highest reached 31.7 pCi/L. Below the action level, 34 tests (29.3%) came in under 2 pCi/L, against 31.6% statewide, and 38 tests (32.8%) fell between 2 and 4, against 25.3% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 37.9% share point the same way here. USGS geology rates 95% of the county's land high radon potential.

The busiest year on file was 2017, with 21 tests reported; the quietest, 2015, had 6.

Edgar County against Illinois, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Edgar County
Edgar County11637.9%3.2 pCi/LThis county
Illinois, pooled102 counties, pooled108,90943.1%Not pooled+5.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−2.2 points
Stark Countyhighest in the state8780.5%7.4 pCi/L+42.6 points
Williamson Countylowest in the state60113.3%1.3 pCi/L−24.6 points
Champaign County, ILborders it8,59350.2%4.0 pCi/L+12.3 points
Vermilion County, ILborders it37948.8%3.8 pCi/L+10.9 points
Vigo County, INborders it45544.0%3.6 pCi/L+6.1 points
Douglas County, ILborders it23442.7%3.4 pCi/L+4.8 points
Vermillion County, INborders it2441.7%3.3 pCi/L+3.8 points
Coles County, ILborders it29538.6%3.1 pCi/L+0.7 points
Clark County, ILborders it7722.1%2.0 pCi/L−15.8 points
Where Edgar County's reported results fell, 2008 to 2017, laboratory, beside Illinois and the United States
ResultEdgar County testsEdgar County shareIllinois shareU.S. shareAgainst Illinois
Under 2 pCi/L3429.3%31.6%39.6%−2.3 points
2 to 4 pCi/L3832.8%25.3%24.7%+7.5 points
4 pCi/L and above4437.9%43.1%35.7%−5.2 points
Edgar County ranked among the 93 Illinois counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Grundy County55 of 9334240.9%3.1 pCi/L
Randolph County56 of 9313440.3%3.2 pCi/L
Jersey County57 of 939038.9%3.2 pCi/L
Coles County58 of 9329538.6%3.1 pCi/L
Cass County59 of 935238.5%3.0 pCi/L
Edgar County60 of 9311637.9%3.2 pCi/L
Effingham County61 of 9376337.9%3.0 pCi/L
Brown County62 of 933737.8%2.9 pCi/L
DuPage County63 of 936,13037.5%2.9 pCi/L
Madison County64 of 933,34337.4%3.0 pCi/L
Montgomery County65 of 9323636.9%2.8 pCi/L
Edgar County radon tests by year, against Illinois' pooled share
YearTestsAt or above 4 pCi/LMedianHighestIllinois, pooledChange from the row before
20172157.1%4.5 pCi/L18.5 pCi/L33.7%+7.1 points
2015650.0%5.8 pCi/L8.5 pCi/L36.6%−50.0 points
20146100.0%4.2 pCi/L4.2 pCi/L37.8%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Edgar County, Geology

The ground under Edgar County

Predicted

Most of the ground under Edgar County is one class on USGS's geologic map: 94.9% of its land is high radon potential, with 5.1% moderate. The map puts 94.9% of Edgar County in the area it calls Bloomington Ridged Plain and 5.1% in Southern Central Lowland Province. USGS gives the first a radon index of 13, in the high band (12 to 17), and the second 9, in the moderate band (9 to 11).

USGS's geologic areas under Edgar County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Bloomington Ridged PlainWisconsinan glacial deposits and loess over Paleozoic sedimentary rocks.High1394.9%
Southern Central Lowland ProvinceIllinoian glacial deposits, sandstone, and gray shale.Moderate95.1%

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

Edgar County beside the ground around it

Edgar County has more high-potential ground than Illinois as a whole: 94.9% of its land against 64.5%. Of the 7 counties that border it, 5 have more high-potential ground, Champaign County the most at 100%.

Share of land by USGS radon potential: Edgar County, the 7 counties bordering it and Illinois
AreaEPA zoneLow potentialModerate potentialHigh potential
Edgar CountyZone 1None5.1%94.9%
Vermillion County, INZone 1None1.0%99.0%
Clark CountyZone 2None96.5%3.5%
Vigo County, INZone 2None86.2%13.8%
Coles CountyZone 1None1.9%98.1%
Douglas CountyZone 1NoneNone100%
Champaign CountyZone 1NoneNone100%
Vermilion CountyZone 1NoneNone100%
Illinois102 counties, pooled by land areaVaries0.9%34.5%64.5%

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

Local help

Edgar County, Local resources

Radon testing and mitigation in Edgar County

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.

What it means

Edgar County, Questions

Questions about radon in Edgar County

Are radon levels high in Edgar County?

In 2017, 57.1% of the radon tests reported to CDC for Edgar County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.5 pCi/L. Of 93 Illinois counties with 30 or more tests for the same period, 59 reported a higher share; pooled, the state comes to 43.1%.

Which counties border Edgar County?

Edgar County borders 7 counties: Vermillion County, IN, Clark County, IL, Vigo County, IN, Coles County, IL, Douglas County, IL, Champaign County, IL and Vermilion County, IL.

Products

Edgar County, Products

Testing a home in Edgar County

In Edgar County, 37.9% of 116 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 43.1% pooled across Illinois. In Zone 1 the year-round level in Edgar County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Edgar County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Edgar County

Explore

Edgar County, Bordering counties

Counties bordering Edgar County

Calculated by Radon411

Edgar County, Cities and towns

Cities and towns in Edgar County

About 16,323 people live in Edgar County by the Census Bureau's estimate for July 1, 2025, 483 fewer than in 2020 (−2.9%). That works out to 26 people per square mile of land. Its largest town, Paris, has 8,026 residents, 49.2% of the total. Together its 8 incorporated places hold 67.2% of those residents; the other 32.8% live outside any of them. CDC's 116 reported tests for 2008 to 2017 work out to 7.1 per 1,000 residents (2025 estimate), close to Illinois' 8.6.

From Paris to Redmon, CDC publishes no figure by town: each reads Edgar County's.

The cities and towns in Edgar County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Paris8,026−2.8%49.2%
Chrisman1,263−2.6%7.7%
Kansas647−3.1%4.0%
Hume314−3.1%1.9%
Brocton262−3.3%1.6%
Vermilion196−3.9%1.2%
Metcalf135−2.9%0.8%
Redmon133−4.3%0.8%

8 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Edgar County, Homes

Homes in Edgar County

Edgar County is a place of houses on their own lots: 78% of its 8,236 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1964, close to Illinois' 1970: 46% date from before 1960 and 12% from 2000 or later. 73% of occupied homes are lived in by their owner (Illinois: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Edgar County, Illinois, 2019 to 2023
HomesEdgar CountyIllinois
Housing units8,2365,443,501
Detached houses78%58%
In buildings of 5 or more6%22%
Mobile homes9%2%
Built before 196046%38%
Built since 200012%16%
Middle year built19641970
Owner-occupied73%67%

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