Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
Locations and reports
Radon Levels in Effingham County, Illinois
EPA puts Effingham County in Zone 2, its middle radon zone, and 38.3% of its 141 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
38.3%
4.6 pts above IL
- Effingham
- 38.3%
- Illinois
- 33.7%
141 tests, 2017
Median result
2.7pCi/L
Below action level
- Effingham
- 2.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
141
46th of 70 by tests
- Effingham
- 141
- 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
45 of 70
Middle half
- Effingham
- 38.3%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Effingham County
Starts at Effingham County's median, 2.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.7 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. Effingham County's median reported result, 2017.
The data
Effingham County, At a glance
Effingham County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Effingham 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 Effingham County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 60.5% |
| 2015 | 50.0% |
| 2017 | 38.3% |
2017: 38.3%. Across these years the share ran from 38.3% to 60.5%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 141 tests reported to CDC for Effingham 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).
Effingham County, Compared
Effingham County radon figures, compared
Calculated by Radon411In Effingham County, about 4 in 10 reported tests in 2017 (54 of 141) were at or above EPA's action level. Against the national pool of 31.7%, the gap is 6.6 points higher. Across 93 Illinois counties pooled together, 33.7% of tests reached that level, so Effingham County runs 4.6 points above its state.
Fayette County, the one bordering county with a figure for the same period, reported 26.3%. By share, Effingham County is 45th of 70 Illinois counties with 30 or more tests for the same period.
Half the tests came in under 2.7 pCi/L and half over it; the single highest reached 19.5 pCi/L. Below the action level, 33 tests (23.4%) came in under 2 pCi/L, against 37.7% statewide, and 54 tests (38.3%) fell between 2 and 4, against 28.6% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 38.3% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential.
The busiest year on file was 2014, with 258 tests reported; the quietest, 2015, had 18.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Effingham County, Geology
The ground under Effingham County
PredictedUSGS's geologic map puts all of Effingham 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.
Effingham County beside the ground around it
Across Illinois 64.5% of the land is rated high; none of Effingham County's is. Of the 5 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
Effingham County, Local resources
Radon testing and mitigation in Effingham County
Listed radon businesses with an address in Effingham 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.
Listed radon professionals by town: Effingham
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
Effingham County, Questions
Questions about radon in Effingham County
Are radon levels high in Effingham County?
In 2017, 38.3% of the radon tests reported to CDC for Effingham County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.7 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 44 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Effingham County?
Effingham County borders 5 counties: Clay County, Jasper County, Fayette County, Cumberland County and Shelby County.
Products
Effingham County, Products
Testing a home in Effingham County
In Effingham County, 38.3% of 141 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 Effingham County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Monitor
Corentium Home battery digital radon detector
- C-NRPP 2024/25: Approved
- Battery
- Screen
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Effingham County, Bordering counties
Counties bordering Effingham 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 · 33.1 points above Effingham County
- Radon levels in Jasper CountyEPA zone 2
50.0%at or above 4 pCi/L
Median 5.9 pCi/L · 6 tests · 11.7 points above Effingham County
- Radon levels in Fayette CountyEPA zone 2
26.3%at or above 4 pCi/L
Median 2.5 pCi/L · 57 tests · 12.0 points below Effingham County
- Radon levels in Cumberland CountyEPA zone 2
25.0%at or above 4 pCi/L
Median 2.8 pCi/L · 12 tests · 13.3 points below Effingham County
- Radon levels in Clay CountyEPA zone 2
No CDC figure for 2017; its page reads it against its own neighbours.
Effingham County, Cities and towns
Cities and towns in Effingham County
About 34,519 people live in Effingham County by the Census Bureau's estimate for July 1, 2025, 176 fewer than in 2020 (−0.5%). That works out to 72 people per square mile of land. Its largest town, Effingham, has 12,406 residents, 35.9% of the total. Reported testing is thin here: 141 tests over 2017, or 4.1 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 10.9.
From Effingham to Shumway, CDC publishes no figure by town: each reads Effingham County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Effingham | 12,406 | +0.6% | 35.9% |
| Altamont | 2,186 | −1.4% | 6.3% |
| Teutopolis | 1,721 | +5.8% | 5.0% |
| Dieterich | 882 | −1.7% | 2.6% |
| Watson | 658 | −1.6% | 1.9% |
| Beecher City | 425 | −0.7% | 1.2% |
| Edgewood | 390 | −1.8% | 1.1% |
| Mason | 321 | −0.9% | 0.9% |
| Montroseextends beyond Effingham County | 211 | −0.9% | Counted whole |
| Shumway | 185 | −1.6% | 0.5% |
10 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 Effingham County is counted whole, so it has no share.
Effingham County, Homes
Homes in Effingham County
Effingham County is a place of houses on their own lots: 79% of its 15,336 homes are detached single-family houses, against 58% across Illinois. Much of Effingham County is recent building: 19% of its homes have gone up since 2000 and the middle year built is 1978, against 1970 for Illinois. Owners live in 78% of the occupied homes (Illinois: 67%), so for most households a test and a fix are their own to order.
| Homes | Effingham County | Illinois |
|---|---|---|
| Housing units | 15,336 | 5,443,501 |
| Detached houses | 79% | 58% |
| In buildings of 5 or more | 6% | 22% |
| Mobile homes | 8% | 2% |
| Built before 1960 | 28% | 38% |
| Built since 2000 | 19% | 16% |
| Middle year built | 1978 | 1970 |
| Owner-occupied | 78% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.