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 Franklin County, Illinois
EPA puts Franklin County in Zone 2, its middle radon zone, and most reported tests there come back low, though 10.0% of 30 (2017) reached 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
10.0%
23.7 pts below IL
- Franklin
- 10.0%
- Illinois
- 33.7%
30 tests, 2017
Median result
1.9pCi/L
Below action level
- Franklin
- 1.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
30
70th of 70 by tests
- Franklin
- 30
- 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
69 of 70
Lowest quarter
- Franklin
- 10.0%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Franklin County
Starts at Franklin 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. Franklin County's median reported result, 2017.
The data
Franklin County, At a glance
Franklin County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Franklin 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 Franklin County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 25.0% |
| 2015 | 50.0% |
| 2017 | 10.0% |
2017: 10.0%. Across these years the share ran from 10.0% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 30 tests reported to CDC for Franklin 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).
Franklin County, Compared
Franklin County radon figures, compared
Calculated by Radon411Franklin County reports fewer high tests than Illinois overall. 10.0% of its 30 tests in 2017 were at or above 4 pCi/L. That is 23.7 points below the 33.7% pooled from 93 Illinois counties.
Ordered from highest share down, it comes 69th of 70 Illinois counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 31.7%; Franklin County sits 21.7 points below it.
Next door, the shares run from 8.4% in Williamson County to 25.0% in Jackson County, with Williamson County below Franklin County. Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 10.0% share point the same way here.
Half the tests came in under 1.9 pCi/L and half over it; the single highest reached 5.9 pCi/L. The rest split 50.0% under 2 pCi/L and 40.0% from 2 to 4 (Illinois: 37.7% and 28.6%).
The busiest year on file was 2017, with 30 tests reported; the quietest, 2015, had 6.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Franklin County, Geology
The ground under Franklin County
PredictedUSGS's geologic map puts all of Franklin 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.
Franklin County beside the ground around it
Across Illinois 64.5% of the land is rated high; none of Franklin County's is. Of the 6 counties that border it, none has as large a share of moderate-potential ground; Hamilton County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Franklin County, Local resources
Radon testing and mitigation in Franklin 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
Franklin County, Questions
Questions about radon in Franklin County
Are radon levels high in Franklin County?
In 2017, 10.0% of the radon tests reported to CDC for Franklin 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, 68 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Franklin County?
Franklin County borders 6 counties: Williamson County, Hamilton County, Jefferson County, Perry County, Saline County and Jackson County.
Products
Franklin County, Products
Testing a home in Franklin County
In Franklin County, 10.0% of 30 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 Franklin 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
MonitorX-Sense
XR0B-SR battery digital radon monitor with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- 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
Franklin County, Bordering counties
Counties bordering Franklin County
Calculated by Radon411- Radon levels in Perry CountyEPA zone 2
40.0%at or above 4 pCi/L
Median 1.5 pCi/L · 15 tests · 30.0 points above Franklin County
- Radon levels in Jackson CountyEPA zone 2
25.0%at or above 4 pCi/L
Median 2.5 pCi/L · 96 tests · 15.0 points above Franklin County
- Radon levels in Jefferson CountyEPA zone 2
19.6%at or above 4 pCi/L
Median 1.9 pCi/L · 138 tests · 9.6 points above Franklin County
- Radon levels in Williamson CountyEPA zone 2
8.4%at or above 4 pCi/L
Median 0.9 pCi/L · 249 tests · 1.6 points below Franklin County
- Radon levels in Saline CountyEPA zone 2
0.0%at or above 4 pCi/L
Median 1.6 pCi/L · 12 tests · 10.0 points below Franklin County
- Radon levels in Hamilton CountyEPA zone 2
No CDC figure for 2017; its page reads it against its own neighbours.
Franklin County, Cities and towns
Cities and towns in Franklin County
About 36,916 people live in Franklin County by the Census Bureau's estimate for July 1, 2025, 778 fewer than in 2020 (−2.1%). That works out to 90 people per square mile of land. No town dominates: West Frankfort, the largest, has 7,105 residents, 19.2% of the total. Reported testing is thin here: 30 tests over 2017, or 0.8 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 10.9.
From West Frankfort to Macedonia, CDC publishes no figure by town: each reads Franklin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| West Frankfort | 7,105 | −2.1% | 19.2% |
| Benton | 6,558 | −2.1% | 17.8% |
| Christopher | 2,607 | −2.7% | 7.1% |
| Sesser | 1,888 | −0.3% | 5.1% |
| Zeigler | 1,456 | −1.8% | 3.9% |
| Royalton | 1,031 | −2.6% | 2.8% |
| West City | 640 | −2.6% | 1.7% |
| Valier | 538 | −2.5% | 1.5% |
| North City | 503 | −1.2% | 1.4% |
| Thompsonville | 477 | −1.6% | 1.3% |
| Buckner | 393 | −2.5% | 1.1% |
| Orient | 321 | −2.4% | 0.9% |
- Hanaford
- Ewing
- Freeman Spur (part)
- Macedonia (part)
16 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).
Franklin County, Homes
Homes in Franklin County
Franklin County is a place of houses on their own lots: 78% of its 18,468 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1965, close to Illinois' 1970: 44% date from before 1960 and 13% 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 | Franklin County | Illinois |
|---|---|---|
| Housing units | 18,468 | 5,443,501 |
| Detached houses | 78% | 58% |
| In buildings of 5 or more | 2% | 22% |
| Mobile homes | 11% | 2% |
| Built before 1960 | 44% | 38% |
| Built since 2000 | 13% | 16% |
| Middle year built | 1965 | 1970 |
| Owner-occupied | 75% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.