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
Locations and reports
Radon Levels in Iroquois County, Illinois
EPA puts Iroquois County in Zone 1, its highest radon zone, and 25.0% of its 36 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
25.0%
8.7 pts below IL
- Iroquois
- 25.0%
- Illinois
- 33.7%
36 tests, 2017
Median result
1.9pCi/L
Below action level
- Iroquois
- 1.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
36
69th of 70 by tests
- Iroquois
- 36
- Cook
- 26,937
Reported to CDC before any fix, 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Illinois
62 of 70
Lowest quarter
- Iroquois
- 25.0%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Iroquois County
Starts at Iroquois County's median, 1.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.9 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Iroquois County's median reported result, 2017.
The data
Iroquois County, At a glance
Iroquois County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Iroquois County in
USGS geologic potential: High across 68% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Iroquois County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 30.0% |
| 2015 | 22.2% |
| 2017 | 25.0% |
2017: 25.0%. Across these years the share ran from 22.2% to 30.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 36 tests reported to CDC for Iroquois 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).
Iroquois County, Compared
Iroquois County radon figures, compared
Calculated by Radon411Iroquois County's 36 reported tests in 2017 had a middle value of 1.9 pCi/L and a maximum of 9.3 pCi/L, and 25.0% reached 4 pCi/L. Illinois as a whole (93 Illinois counties, pooled) comes to 33.7%: 8.7 points higher than here.
Among its state's counties it ranks 62nd 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, 21 tests (58.3%) came in under 2 pCi/L, against 37.7% statewide, and 6 tests (16.7%) fell between 2 and 4, against 28.6% statewide. The busiest year on file was 2014, with 60 tests reported; the quietest, 2015, had 27.
EPA's 1993 zone map puts Iroquois County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 68% of the county's land high radon potential.
Next door, the shares run from 31.6% in Kankakee County to 57.1% in Ford County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Iroquois County, Geology
The ground under Iroquois County
PredictedUSGS's geologic map splits Iroquois County: 68.0% of its land is high radon potential and 32.0% moderate. The map puts 68.0% of Iroquois County in the area it calls Bloomington Ridged Plain and 32.0% in Kankakee Plain. USGS gives the first a radon index of 13, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Bloomington Ridged Plain | Wisconsinan glacial deposits and loess over Paleozoic sedimentary rocks. | High | 13 | 68.0% |
| Kankakee Plain | Eolian quartz sand deposits. | Moderate | 11 | 32.0% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Iroquois County beside the ground around it
On high-potential ground Iroquois County is close to Illinois as a whole: 68.0% of its land against 64.5%. Of the 5 counties that border it, 3 have more high-potential ground, Benton County, IN the most at 100%.
The map rates the ground, not the air in any home.
Local help
Iroquois County, Local resources
Radon testing and mitigation in Iroquois 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
Iroquois County, Questions
Questions about radon in Iroquois County
Are radon levels high in Iroquois County?
In 2017, 25.0% of the radon tests reported to CDC for Iroquois County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.9 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 61 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Iroquois County?
Iroquois County borders 5 counties: Kankakee County, IL, Ford County, IL, Newton County, IN, Benton County, IN and Vermilion County, IL.
Products
Iroquois County, Products
Testing a home in Iroquois County
In Iroquois County, 25.0% of 36 tests reported to CDC in 2017 reached 4 pCi/L, against 33.7% pooled across Illinois. In Zone 1 the year-round level in Iroquois 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
Monitor
RadonPro Wi-Fi radon monitor with a built-in Geiger counter
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Iroquois County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Iroquois County
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Iroquois County, Bordering counties
Counties bordering Iroquois County
Calculated by Radon411- Radon levels in Ford County, ILEPA zone 1
57.1%at or above 4 pCi/L
Median 4.0 pCi/L · 42 tests · 32.1 points above Iroquois County
- Radon levels in Vermilion County, ILEPA zone 1
53.8%at or above 4 pCi/L
Median 4.7 pCi/L · 39 tests · 28.8 points above Iroquois County
- Radon levels in Kankakee County, ILEPA zone 2
31.6%at or above 4 pCi/L
Median 2.7 pCi/L · 522 tests · 6.6 points above Iroquois County
- Radon levels in Newton County, INEPA zone 2
No CDC figure for 2017; its page reads it against its own neighbours.
- Radon levels in Benton County, INEPA zone 1
No CDC figure for 2017; its page reads it against its own neighbours.
Iroquois County, Cities and towns
Cities and towns in Iroquois County
About 26,150 people live in Iroquois County by the Census Bureau's estimate for July 1, 2025, 817 fewer than in 2020 (−3.0%). That works out to 23 people per square mile of land. No town dominates: Watseka, the largest, has 4,510 residents, 17.2% of the total. Reported testing is thin here: 36 tests over 2017, or 1.4 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 10.9.
From Watseka to Iroquois, CDC publishes no figure by town: each reads Iroquois County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Watseka | 4,510 | −3.5% | 17.2% |
| Gilman | 1,681 | −3.7% | 6.4% |
| Onarga | 1,305 | −3.0% | 5.0% |
| Clifton | 1,298 | −3.6% | 5.0% |
| Milford | 1,116 | −3.6% | 4.3% |
| Chebanseextends beyond Iroquois County | 1,014 | −3.4% | Counted whole |
| Sheldon | 931 | −3.6% | 3.6% |
| Cissna Park | 780 | −3.7% | 3.0% |
| Ashkum | 718 | −3.4% | 2.7% |
| Danforth | 569 | −3.4% | 2.2% |
| Crescent City | 529 | −4.0% | 2.0% |
| Buckley | 462 | −3.8% | 1.8% |
- Loda
- Martinton
- Beaverville
- Donovan
- Woodland
- Thawville
- Wellington
- Papineau
- Iroquois
21 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Iroquois County is counted whole, so it has no share.
Iroquois County, Homes
Homes in Iroquois County
Iroquois County is a place of houses on their own lots: 85% of its 12,818 homes are detached single-family houses, against 58% across Illinois. The homes are older than Illinois' as a whole: half were built before 1960 (1970 for Illinois), and 50% date from before 1960. Owners live in 79% of the occupied homes (Illinois: 67%), so for most households a test and a fix are their own to order.
| Homes | Iroquois County | Illinois |
|---|---|---|
| Housing units | 12,818 | 5,443,501 |
| Detached houses | 85% | 58% |
| In buildings of 5 or more | 3% | 22% |
| Mobile homes | 4% | 2% |
| Built before 1960 | 50% | 38% |
| Built since 2000 | 8% | 16% |
| Middle year built | 1960 | 1970 |
| Owner-occupied | 79% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.