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Radon Levels in Saline County, Illinois

EPA puts Saline County in Zone 2, its middle radon zone, and only 12 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

    18.1%

    25.6 pts below IL

    Saline
    18.1%
    Illinois
    43.7%

    83 tests, 2007 to 2016

  • Median result

    1.7pCi/L

    Below action level

    Saline
    1.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2007 to 2016

  • Tests reported

    83

    76th of 92 by tests

    Saline
    83
    Cook
    13,699

    Reported to CDC before any fix, 2007 to 2016

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Illinois

    85 of 92

    Lowest quarter

    Saline
    18.1%
    Stark
    79.4%

    By share, of 92 with 30+ tests

Read a result for Saline County

Starts at Saline County's median, 1.7 pCi/L

1.7pCi/L

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

EPA’s reading of 1.7 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Saline County's median reported result, 2007 to 2016.

Interpret this reading

The data

Saline County, At a glance

Saline County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Saline County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Saline County, 2017

Share of reported tests at or above 4 pCi/L, by year, Saline County
Share of reported tests at or above 4 pCi/L, by year, Saline County
YearShare of reported tests at or above 4 pCi/L
20140.0%
20150.0%
20170.0%

2017: 0.0%. Across these years the share ran from 0.0% to 0.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 12 tests were reported to CDC for Saline 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

Saline County, Compared

Saline County radon figures, compared

Calculated by Radon411

Saline County's 83 reported tests over the 2007 to 2016 laboratory totals had a middle value of 1.7 pCi/L and a maximum of 9.2 pCi/L, and 18.1% reached 4 pCi/L. Illinois as a whole (102 Illinois counties, pooled) comes to 43.7%: 25.6 points higher than here.

The newest figure, in 2017, counts only 12 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 83-test figure.

Among its state's counties it ranks 85th of 92 Illinois counties with 30 or more tests for the same period. Statewide for the same period, Stark County reported the highest share (79.4%) and Johnson County the lowest (12.2%).

Below the action level, 48 tests (57.8%) came in under 2 pCi/L, against 31.2% statewide, and 20 tests (24.1%) fell between 2 and 4, against 25.1% statewide. The busiest year on file was 2014, with 12 tests reported; the quietest, 2015, had 9.

EPA's 1993 zone map puts Saline County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Next door, the shares run from 12.2% in Johnson County to 23.3% in Hamilton County, with Williamson County and Johnson County below Saline County.

Saline County against Illinois, the United States and nearby counties, 2007 to 2016, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Saline County
Saline County8318.1%1.7 pCi/LThis county
Illinois, pooled102 counties, pooled105,29343.7%Not pooled+25.6 points
United States, pooled2,666 counties, pooled1,939,02535.8%Not pooled+17.7 points
Stark Countyhighest in the state6879.4%7.8 pCi/L+61.3 points
Wayne Countylowest in the state8714.9%1.4 pCi/L−3.2 points
Hardin County, ILborders it1030.0%2.4 pCi/L+11.9 points
Hamilton County, ILborders it3023.3%1.9 pCi/L+5.2 points
Franklin County, ILborders it21019.0%1.8 pCi/L+0.9 points
Williamson County, ILborders it60513.6%1.3 pCi/L−4.5 points
Johnson County, ILborders it4912.2%1.8 pCi/L−5.9 points
Gallatin County, ILborders it70.0%1.9 pCi/L−18.1 points
Pope County, ILborders it80.0%1.8 pCi/L−18.1 points
Where Saline County's reported results fell, 2007 to 2016, laboratory, beside Illinois and the United States
ResultSaline County testsSaline County shareIllinois shareU.S. shareAgainst Illinois
Under 2 pCi/L4857.8%31.2%39.6%+26.6 points
2 to 4 pCi/L2024.1%25.1%24.6%−1.0 points
4 pCi/L and above1518.1%43.7%35.8%−25.6 points
Saline County ranked among the 92 Illinois counties with 30 or more tests, by share at or above 4 pCi/L, 2007 to 2016, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Cumberland County80 of 925020.0%1.7 pCi/L
Marion County81 of 9238719.9%1.8 pCi/L
Crawford County82 of 9217519.4%1.8 pCi/L
Richland County83 of 9214019.3%1.9 pCi/L
Franklin County84 of 9221019.0%1.8 pCi/L
Saline County85 of 928318.1%1.7 pCi/L
Clay County86 of 926917.4%1.1 pCi/L
Clark County87 of 927517.3%1.8 pCi/L
Massac County88 of 923517.1%2.2 pCi/L
Lawrence County89 of 924615.2%1.8 pCi/L
Wayne County90 of 928714.9%1.4 pCi/L
Saline County radon tests by year, against Illinois' pooled share
YearTestsAt or above 4 pCi/LMedianHighestIllinois, pooledChange from the row before
2017120.0%1.6 pCi/L2.6 pCi/L33.7%Level
201590.0%1.0 pCi/L1.5 pCi/L36.6%Level
2014120.0%1.4 pCi/L1.6 pCi/L37.8%First on file

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

Saline County, Geology

The ground under Saline County

Predicted

USGS's geologic map puts all of Saline County's mapped land in one class: moderate radon potential. The map puts 61.8% of Saline County in the area it calls Shawnee Hills Section and 38.2% in Southern Central Lowland Province. USGS gives the first a radon index of 10 and the second 9, both in the moderate band (9 to 11).

USGS's geologic areas under Saline County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Shawnee Hills SectionUnglaciated Ordovician to Pennsylvanian limestone, sandstone, and shale.Moderate1061.8%
Southern Central Lowland ProvinceIllinoian glacial deposits, sandstone, and gray shale.Moderate938.2%

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

Saline County beside the ground around it

Across Illinois 64.5% of the land is rated high; none of Saline County's is. Of the 7 counties that border it, none has as large a share of moderate-potential ground; Franklin County comes nearest at 100%.

Share of land by USGS radon potential: Saline County, the 7 counties bordering it and Illinois
AreaEPA zoneLow potentialModerate potentialHigh potential
Saline CountyZone 2None100%None
Gallatin CountyZone 2None100%None
Hamilton CountyZone 2None100%None
Williamson CountyZone 2None100%None
Hardin CountyZone 2None100%None
Johnson CountyZone 22.7%97.3%None
Franklin CountyZone 2None100%None
Pope CountyZone 22.8%97.2%None
Illinois102 counties, pooled by land areaVaries0.9%34.5%64.5%

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

Local help

Saline County, Local resources

Radon testing and mitigation in Saline 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

Saline County, Questions

Questions about radon in Saline County

Are radon levels high in Saline County?

In 2017, 0.0% of the radon tests reported to CDC for Saline County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.6 pCi/L. Of 92 Illinois counties with 30 or more tests for the same period, 84 reported a higher share; pooled, the state comes to 43.7%.

Which counties border Saline County?

Saline County borders 7 counties: Gallatin County, Hamilton County, Williamson County, Hardin County, Johnson County, Franklin County and Pope County.

Products

Saline County, Products

Testing a home in Saline County

In Saline County, 18.1% of 83 tests reported to CDC over the 2007 to 2016 laboratory totals reached 4 pCi/L, against 43.7% pooled across Illinois. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Saline County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Saline County homes, compared

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Saline County, Bordering counties

Counties bordering Saline County

Calculated by Radon411

Saline County, Cities and towns

Cities and towns in Saline County

About 22,772 people live in Saline County by the Census Bureau's estimate for July 1, 2025, 969 fewer than in 2020 (−4.1%). That works out to 60 people per square mile of land. Its largest town, Harrisburg, has 7,922 residents, 34.8% of the total. Reported testing is thin here: 83 tests over 2007 to 2016, or 3.6 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 8.3.

From Harrisburg to Muddy, CDC publishes no figure by town: each reads Saline County's.

The cities and towns in Saline County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Harrisburg7,922−4.0%34.8%
Eldorado3,579−4.2%15.7%
Carrier Mills1,595−4.1%7.0%
Galatia785−4.3%3.4%
Raleigh276−4.2%1.2%
Stonefortextends beyond Saline County220−1.3%Counted whole
Muddy55−5.2%0.2%

7 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). A place that extends beyond Saline County is counted whole, so it has no share.

Saline County, Homes

Homes in Saline County

Saline County is a place of houses on their own lots: 76% of its 11,578 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1970, close to Illinois' 1970: 41% date from before 1960 and 15% from 2000 or later. 75% 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 Saline County, Illinois, 2019 to 2023
HomesSaline CountyIllinois
Housing units11,5785,443,501
Detached houses76%58%
In buildings of 5 or more8%22%
Mobile homes10%2%
Built before 196041%38%
Built since 200015%16%
Middle year built19701970
Owner-occupied75%67%

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