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Radon in Springfield, Illinois

EPA puts Sangamon County, where Springfield is, in Zone 1, its highest radon zone, and high results are common there: 43.7% of the 3,378 radon tests reported to CDC (2017) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    43.7%

    10.0 pts above IL

    Sangamon
    43.7%
    Illinois
    33.7%

    Sangamon, 36th of 70 in IL, 2017

  • Median result

    3.7pCi/L

    Below action level

    Sangamon
    3.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of Sangamon's tests, 2017

  • Nearest county

    51.8%

    Menard, 19 miles

    Menard
    51.8%
    Sangamon
    43.7%

    168 tests, 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    Sangamon, where Springfield is

  • Tests reported

    3,378

    In Sangamon

    Sangamon
    3,378
    Menard
    168

    Reported to CDC before any fix, 2017

Read a result for Springfield

Starts at Sangamon County's median, 3.7 pCi/L

3.7pCi/L

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

EPA’s reading of 3.7 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. Sangamon County's median reported result, 2017.

Interpret this readingWhat a fix costs

The data

Springfield, What is published

What is published for Springfield

Information:

Every figure for Springfield is a county's

Radon data is published by county, not by city, so for Springfield it is Sangamon County's: its EPA zone (Zone 1) and the 3,378 tests reported to CDC for 2017. Only a test tells you about one home.

Springfield covers 61.1 square miles of land, all of it in Sangamon County. About 112,989 people live there, 1,848 to the square mile.

Springfield, Counties

The county Springfield lies in

Measured

Sangamon County's EPA zone and the figures CDC publishes for it, 2017.

Sangamon CountyZone 1Highest predicted potential

43.7%
Reported tests at or above 4 pCi/L
3.7 pCi/L
Median reported result
3,378 tests
Tests reported to CDC
4
Annual years on file

Sangamon County ranks 36th of 70 Illinois counties with 30 or more tests for that period, 10.0 points above the 33.7% pooled across Illinois's counties, 12.0 points above the national pool of 31.7%.

Measured from the middle of Springfield, the nearest counties with a CDC figure for 2017 are Menard County (19 miles, 51.8% of 168 tests), Christian County (25 miles, 42.3% of 213 tests) and Logan County (29 miles, 45.8% of 72 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 21.4% to 66.9%; the farthest of them, Montgomery County, is 38 miles away at 43.9%.

The directory lists 3 businesses with an address in Springfield, 3 for testing. Illinois's other cities with a page of their own: Chicago, Rockford, Naperville and Glenview.

The counties around Springfield

By distance from the middle of Springfield; counties with 30 or more tests.

Nearest counties to Springfield with 30 or more tests
CountyDistanceTestsAt or above 4 pCi/LMedian
Menard County19 mi16851.8%4.3 pCi/L
Christian County25 mi21342.3%3.5 pCi/L
Logan County29 mi7245.8%3.4 pCi/L
Morgan County29 mi38166.9%6.5 pCi/L
Mason County35 mi4221.4%2.8 pCi/L
Macon County37 mi1,25138.8%3.1 pCi/L
Macoupin County38 mi25825.6%2.2 pCi/L
Montgomery County38 mi12343.9%3.3 pCi/L

Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2017.

Springfield, Geology

The ground under Springfield

Predicted

USGS's geologic map puts all of Springfield's mapped land in one class: high radon potential. All of it lies in the area the map calls Galesburg Plain, to which USGS gives a radon index of 13, in the high band (12 to 17).

USGS's geologic areas under Springfield
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Galesburg PlainIllinoian glacial deposits and loess over Paleozoic sedimentary rocks.High13100%

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

Springfield beside its county and Illinois

All of Springfield, like all of Sangamon County, is rated high. Springfield has more high-potential ground than Illinois as a whole: 100% of its land against 64.5%.

Share of land by USGS radon potential: Springfield, the county it lies in and Illinois
AreaEPA zoneLow potentialModerate potentialHigh potential
SpringfieldBy countyNoneNone100%
Sangamon CountyZone 1NoneNone100%
Illinois102 counties, pooled by land areaVaries0.9%34.5%64.5%

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

Springfield, Homes

Homes in Springfield

Of Springfield's 57,220 homes, 65% are detached houses, against 73% across Sangamon County; 17% are in buildings of five or more homes. Half of its homes were built before 1971, close to Sangamon County's 1973: 35% date from before 1960 and 12% from 2000 or later. 63% of occupied homes are lived in by their owner (Sangamon County: 71%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Springfield, Sangamon County, Illinois, 2019 to 2023
HomesSpringfieldSangamon CountyIllinois
Housing units57,22093,1515,443,501
Detached houses65%73%58%
In buildings of 5 or more17%12%22%
Mobile homes3%4%2%
Built before 196035%33%38%
Built since 200012%15%16%
Middle year built197119731970
Owner-occupied63%71%67%

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

Local help

Springfield, Professionals

Radon professionals listed in Springfield

Businesses whose listed city is Springfield, from the state registries and listings in the Radon411 directory, with the same business and certification status the directory shows.

3 listings with Springfield as the city. See radon testing in Springfield, or all radon professionals in Illinois.

Springfield, Local resources

Local resources for Springfield

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

The program's own words on licensing and disclosure are on the Illinois page.

What it means

Springfield, Questions

Questions about radon in Springfield

What radon zone is Springfield in?

Springfield has no zone of its own: it shares Sangamon County's, Zone 1, the map's highest class: a predicted county average above 4 pCi/L.

What are radon levels in Springfield?

High results are ordinary around Springfield: 43.7% of the 3,378 tests reported from Sangamon County for 2017 were at or above 4 pCi/L, the level at which EPA says to fix a home. The median reported result was 3.7 pCi/L.

Should I test my home in Springfield?

Yes. Sangamon County reported about 1,476 of its 3,378 tests at or above 4 pCi/L. That is above Illinois' pooled 33.7%, and ranks Sangamon County 36th of the 70 Illinois counties with 30 or more tests. Which homes they were, no map can say. How to test a home.

What ground is Springfield built on, as far as radon goes?

USGS's geologic map puts all of Springfield on one named area, "Galesburg Plain", rated high for radon potential, radon index 13.

Is radon higher in the counties around Springfield?

It depends which way you go. 4 of the 8 nearest counties with a figure report a larger share than Sangamon County's 43.7% and 4 a smaller one: from Mason County (21.4%, 35 miles off) to Morgan County (66.9%, 29 miles off).

Who tests for or fixes radon in Springfield?

Springfield is the address of 3 businesses in Radon411's directory, all listed for testing, none for mitigation. Each entry names the public list it came from. Radon professionals in Springfield.

The answers use the published figures of Sangamon County, the county Springfield lies in.

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