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 Menard County, Illinois
EPA puts Menard County in Zone 1, its highest radon zone, and high results are common there: 51.8% of the 168 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
Share at 4+ pCi/L
51.8%
18.1 pts above IL
- Menard
- 51.8%
- Illinois
- 33.7%
168 tests, 2017
Median result
4.3pCi/L
Action level reached
- Menard
- 4.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
168
44th of 70 by tests
- Menard
- 168
- 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
19 of 70
Middle half
- Menard
- 51.8%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Menard County
Starts at Menard County's median, 4.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.3 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Menard County's median reported result, 2017.
The data
Menard County, At a glance
Menard County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Menard County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Menard County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 36.2% |
| 2015 | 35.6% |
| 2017 | 51.8% |
2017: 51.8%. Across these years the share ran from 35.6% to 51.8%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 168 tests reported to CDC for Menard 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).
Menard County, Compared
Menard County radon figures, compared
Calculated by Radon411More than half: 51.8% of the 168 radon tests reported to CDC for Menard County in 2017 read at least 4 pCi/L. That places it 19th of 70 Illinois counties with 30 or more tests for the same period. That is 18.1 points above the 33.7% pooled from 93 Illinois counties.
The median result, 4.3 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 16.9 pCi/L. The rest split 16.1% under 2 pCi/L and 32.1% from 2 to 4 (Illinois: 37.7% and 28.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 51.8% share point the same way here.
No bordering county with a figure for the same period reported a higher share; the closest is Logan County at 45.8%, the lowest Mason County at 21.4%. Statewide for the same period, Stark County reported the highest share (69.2%) and Williamson County the lowest (8.4%).
The busiest year on file was 2014, with 282 tests reported; the quietest, 2015, had 135.
Over 3 years of annual figures the share rose 15.6 points, from 36.2% in 2014 to 51.8% in 2017; its peak was 51.8% in 2017. Nationally, every county with a figure for the same period pools to 31.7%; Menard County sits 20.1 points above it.
Menard CountyIllinois, pooled
51.8% % of tests33.7% % of tests
| Year | Tests | Menard County, at or above 4 pCi/L | Illinois, pooled |
|---|---|---|---|
| 2014 | 282 | 36.2% | 37.8% |
| 2015 | 135 | 35.6% | 36.6% |
| 2017 | 168 | 51.8% | 33.7% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Menard County, Geology
The ground under Menard County
PredictedUSGS's geologic map puts all of Menard County'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).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Galesburg Plain | Illinoian glacial deposits and loess over Paleozoic sedimentary rocks. | High | 13 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Menard County beside the ground around it
Menard County has more high-potential ground than Illinois as a whole: 100% of its land against 64.5%. Of the 4 counties that border it, none has as large a share of high-potential ground; Cass County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Menard County, Local resources
Radon testing and mitigation in Menard 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
Menard County, Questions
Questions about radon in Menard County
Are radon levels high in Menard County?
In 2017, 51.8% of the radon tests reported to CDC for Menard County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.3 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 18 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Menard County?
Menard County borders 4 counties: Mason County, Sangamon County, Logan County and Cass County.
Products
Menard County, Products
Testing a home in Menard County
In Menard County, 51.8% of 168 tests reported to CDC in 2017 reached 4 pCi/L, against 33.7% pooled across Illinois. In Zone 1 the year-round level in Menard 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
MonitorAranet
Radon Plus battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Approved
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Menard County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Menard County
Explore
Menard County, Bordering counties
Counties bordering Menard County
Calculated by Radon411- Radon levels in Logan CountyEPA zone 1
45.8%at or above 4 pCi/L
Median 3.4 pCi/L · 72 tests · 6.0 points below Menard County
- Radon levels in Sangamon CountyEPA zone 1
43.7%at or above 4 pCi/L
Median 3.7 pCi/L · 3,378 tests · 8.1 points below Menard County
- Radon levels in Cass CountyEPA zone 1
25.0%at or above 4 pCi/L
Median 2.9 pCi/L · 24 tests · 26.8 points below Menard County
- Radon levels in Mason CountyEPA zone 1
21.4%at or above 4 pCi/L
Median 2.8 pCi/L · 42 tests · 30.4 points below Menard County
Menard County, Cities and towns
Cities and towns in Menard County
About 11,863 people live in Menard County by the Census Bureau's estimate for July 1, 2025, 410 fewer than in 2020 (−3.3%). That works out to 38 people per square mile of land. No town dominates: Petersburg, the largest, has 2,125 residents, 17.9% of the total. Together its 5 incorporated places hold 45.3% of those residents; the other 54.7% live outside any of them. CDC's 168 reported tests for 2017 work out to 14.2 per 1,000 residents (2025 estimate), close to Illinois' 10.9.
From Petersburg to Oakford, CDC publishes no figure by town: each reads Menard County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Petersburg | 2,125 | −4.0% | 17.9% |
| Athens | 1,883 | −4.2% | 15.9% |
| Greenview | 718 | −3.9% | 6.1% |
| Tallula | 420 | −3.2% | 3.5% |
| Oakford | 224 | −3.9% | 1.9% |
5 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).
Menard County, Homes
Homes in Menard County
Menard County is a place of houses on their own lots: 88% of its 5,602 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1975, close to Illinois' 1970: 34% date from before 1960 and 16% from 2000 or later. 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 | Menard County | Illinois |
|---|---|---|
| Housing units | 5,602 | 5,443,501 |
| Detached houses | 88% | 58% |
| In buildings of 5 or more | 4% | 22% |
| Mobile homes | 3% | 2% |
| Built before 1960 | 34% | 38% |
| Built since 2000 | 16% | 16% |
| Middle year built | 1975 | 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.