Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Fayette County, Illinois
EPA puts Fayette County in Zone 2, its middle radon zone, and 26.3% of its 57 reported radon tests (2017) were 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
Share at 4+ pCi/L
26.3%
7.4 pts below IL
- Fayette
- 26.3%
- Illinois
- 33.7%
57 tests, 2017
Median result
2.5pCi/L
Below action level
- Fayette
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
57
59th of 70 by tests
- Fayette
- 57
- Cook
- 26,937
Reported to CDC before any fix, 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Illinois
60 of 70
Lowest quarter
- Fayette
- 26.3%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Fayette County
Starts at Fayette County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Fayette County's median reported result, 2017.
The data
Fayette County, At a glance
Fayette County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Fayette County is a
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 Fayette County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 12.5% |
| 2015 | 25.0% |
| 2017 | 26.3% |
2017: 26.3%. Across these years the share ran from 12.5% to 26.3%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 57 tests reported to CDC for Fayette County over 2017, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2017. Measured data period: 2005 to 2017 (every CDC figure on file).
Fayette County, Compared
Fayette County radon figures, compared
Calculated by Radon411Fayette County's 57 reported tests in 2017 had a middle value of 2.5 pCi/L and a maximum of 7.4 pCi/L, and 26.3% reached 4 pCi/L. Illinois as a whole (93 Illinois counties, pooled) comes to 33.7%: 7.4 points higher than here.
Among its state's counties it ranks 60th of 70 Illinois counties with 30 or more tests for the same period. Statewide for the same period, Stark County reported the highest share (69.2%) and Williamson County the lowest (8.4%).
Below the action level, 18 tests (31.6%) came in under 2 pCi/L, against 37.7% statewide, and 24 tests (42.1%) fell between 2 and 4, against 28.6% statewide. The busiest year on file was 2017, with 57 tests reported; the quietest, 2015, had 24.
EPA's 1993 zone map puts Fayette 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 20.0% in Marion County to 43.9% in Montgomery County, with Marion County below Fayette County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Fayette County, Geology
The ground under Fayette County
PredictedUSGS's geologic map puts all of Fayette County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Southern Central Lowland Province, to which USGS gives a radon index of 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Southern Central Lowland Province | Illinoian glacial deposits, sandstone, and gray shale. | Moderate | 9 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Fayette County beside the ground around it
Across Illinois 64.5% of the land is rated high; none of Fayette County's is. Of the 7 counties that border it, 2 have more high-potential ground, Shelby County the most at 45.1%.
The map rates the ground, not the air in any home.
Local help
Fayette County, Local resources
Radon testing and mitigation in Fayette County
- IEMA-OHS Radon ProgramIEMA-OHS Radon Program, run by Illinois Emergency Management Agency and Office of Homeland Security, licenses or certifies radon professionals and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Illinois.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Illinois339 professionals are listed in Illinois.
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
Fayette County, Questions
Questions about radon in Fayette County
Are radon levels high in Fayette County?
In 2017, 26.3% of the radon tests reported to CDC for Fayette County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 59 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Fayette County?
Fayette County borders 7 counties: Marion County, Bond County, Effingham County, Montgomery County, Clay County, Clinton County and Shelby County.
Products
Fayette County, Products
Testing a home in Fayette County
In Fayette County, 26.3% of 57 tests reported to CDC in 2017 reached 4 pCi/L, against 33.7% pooled across Illinois. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Fayette County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
MonitorX-Sense
XR0A-SR battery digital radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
Method: Alpha spectrometry
First reading: Within 24 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Fayette County, Bordering counties
Counties bordering Fayette County
Calculated by Radon411- Radon levels in Shelby CountyEPA zone 2
71.4%at or above 4 pCi/L
Median 5.2 pCi/L · 21 tests · 45.1 points above Fayette County
- Radon levels in Montgomery CountyEPA zone 2
43.9%at or above 4 pCi/L
Median 3.3 pCi/L · 123 tests · 17.6 points above Fayette County
- Radon levels in Effingham CountyEPA zone 2
38.3%at or above 4 pCi/L
Median 2.7 pCi/L · 141 tests · 12.0 points above Fayette County
- Radon levels in Clinton CountyEPA zone 2
37.6%at or above 4 pCi/L
Median 3.0 pCi/L · 582 tests · 11.3 points above Fayette County
- Radon levels in Bond CountyEPA zone 2
32.0%at or above 4 pCi/L
Median 2.6 pCi/L · 75 tests · 5.7 points above Fayette County
- Radon levels in Marion CountyEPA zone 2
20.0%at or above 4 pCi/L
Median 1.9 pCi/L · 45 tests · 6.3 points below Fayette County
- Radon levels in Clay CountyEPA zone 2
No CDC figure for 2017; its page reads it against its own neighbours.
Fayette County, Cities and towns
Cities and towns in Fayette County
About 20,790 people live in Fayette County by the Census Bureau's estimate for July 1, 2025, 693 fewer than in 2020 (−3.2%). That works out to 29 people per square mile of land. Its largest town, Vandalia, has 7,108 residents, 34.2% of the total. Reported testing is thin here: 57 tests over 2017, or 2.7 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 10.9.
From Vandalia to Bingham, CDC publishes no figure by town: each reads Fayette County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Vandalia | 7,108 | −4.4% | 34.2% |
| St. Elmo | 1,213 | −2.8% | 5.8% |
| Ramsey | 884 | −2.8% | 4.3% |
| Brownstown | 674 | −2.6% | 3.2% |
| Farinaextends beyond Fayette County | 524 | −2.6% | Counted whole |
| St. Peter | 315 | −3.4% | 1.5% |
| Bingham | 58 | −6.5% | 0.3% |
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 Fayette County is counted whole, so it has no share.
Fayette County, Homes
Homes in Fayette County
Fayette County is a place of houses on their own lots: 78% of its 8,849 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1970, close to Illinois' 1970: 40% date from before 1960 and 14% from 2000 or later. Owners live in 80% of the occupied homes (Illinois: 67%), so for most households a test and a fix are their own to order.
| Homes | Fayette County | Illinois |
|---|---|---|
| Housing units | 8,849 | 5,443,501 |
| Detached houses | 78% | 58% |
| In buildings of 5 or more | 2% | 22% |
| Mobile homes | 14% | 2% |
| Built before 1960 | 40% | 38% |
| Built since 2000 | 14% | 16% |
| Middle year built | 1970 | 1970 |
| Owner-occupied | 80% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.