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 Logan County, Ohio
EPA puts Logan County in Zone 1, its highest radon zone, and high results are common there: 73.6% of the 755 radon tests reported to CDC (2008 to 2017, laboratory totals) 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
73.6%
21.3 pts above OH
- Logan
- 73.6%
- Ohio
- 52.3%
755 tests, 2008 to 2017
Median result
7.9pCi/L
Action level reached
- Logan
- 7.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
755
29th of 79 by tests
- Logan
- 755
- Franklin
- 16,142
Reported to CDC before any fix, 2008 to 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 Ohio
3 of 79
Top quarter
- Logan
- 73.6%
- Pickaway
- 81.4%
By share, of 79 with 30+ tests
Read a result for Logan County
Starts at Logan County's median, 7.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 7.9 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. Logan County's median reported result, 2008 to 2017.
The data
Logan County, At a glance
Logan County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Logan 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 Logan County, 2008 to 2017, laboratory
Under 2 pCi/L: 10%2 to 4 pCi/L: 16%4 pCi/L and above: 74%
Of 755 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 75 | 9.9% |
| 2 to 4 pCi/L | 124 | 16.4% |
| 4 pCi/L and above | 556 | 73.6% |
What these figures count
These are the 755 tests reported to CDC for Logan County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Logan County, Compared
Logan County radon figures, compared
Calculated by Radon411More than half: 73.6% of the 755 radon tests reported to CDC for Logan County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 3rd of 79 Ohio counties with 30 or more tests for the same period. That is 21.3 points above the 52.3% pooled from 88 Ohio counties.
The median result, 7.9 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 274.8 pCi/L. The rest split 9.9% under 2 pCi/L and 16.4% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 73.6% share point the same way here.
No bordering county with a figure for the same period reported a higher share; the closest is Auglaize County at 71.2%, the lowest Hardin County at 43.3%. Statewide for the same period, Pickaway County reported the highest share (81.4%) and Cuyahoga County the lowest (21.7%).
CDC's ten-year totals for Logan County went from 597 tests (2005 to 2014) to 755 (2008 to 2017), the share going from 73.9% to 73.6%.
Nationally, every county with a figure for the same period pools to 35.7%; Logan County sits 37.9 points above it. CDC also counts 23 tests taken after mitigation in Logan County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Logan County, Geology
The ground under Logan County
PredictedUSGS's geologic map puts all of Logan County's mapped land in one class: high radon potential. All of it lies in the area the map calls Till Plains, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Till Plains | Glacial deposits underlain by Ordovician through Devonian limestone and shale. | High | 14 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Logan County beside the ground around it
Logan County has more high-potential ground than Ohio as a whole: 100% of its land against 62.8%. Of the 5 counties that border it, none has as large a share of high-potential ground; Auglaize County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Logan County, Local resources
Radon testing and mitigation in Logan County
Listed radon businesses with an address in Logan County:
- Radon Education and Licensing ProgramRadon Education and Licensing Program, run by Ohio Department of Health, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Ohio.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Free radon test kits are available for Ohio homeowners.
- Compare kits
- Professionals in Ohio479 professionals are listed in Ohio.
Listed radon professionals by town: Bellefontaine, West Liberty, Belle Center
What Ohio's program says
- Phone
- 614-728-0272
- indoor.radon@odh.ohio.gov
- Licensing of radon professionals
This program licenses companies and persons directly involved with the radon testing and mitigation industry.
What it means
Logan County, Questions
Questions about radon in Logan County
Are radon levels high in Logan County?
Over the 2008 to 2017 laboratory totals, 73.6% of the radon tests reported to CDC for Logan County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 7.9 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 52.3%.
Which counties border Logan County?
Logan County borders 5 counties: Champaign County, Hardin County, Union County, Shelby County and Auglaize County.
Products
Logan County, Products
Testing a home in Logan County
In Logan County, 73.6% of 755 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 52.3% pooled across Ohio. In Zone 1 the year-round level in Logan 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
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
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
Logan County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Logan County
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Logan County, Bordering counties
Counties bordering Logan County
Calculated by Radon411- Radon levels in Auglaize CountyEPA zone 1
71.2%at or above 4 pCi/L
Median 6.5 pCi/L · 139 tests · 2.4 points below Logan County
- Radon levels in Champaign CountyEPA zone 1
71.1%at or above 4 pCi/L
Median 6.8 pCi/L · 596 tests · 2.5 points below Logan County
- Radon levels in Union CountyEPA zone 1
60.2%at or above 4 pCi/L
Median 4.8 pCi/L · 1,285 tests · 13.4 points below Logan County
- Radon levels in Shelby CountyEPA zone 1
60.1%at or above 4 pCi/L
Median 5.2 pCi/L · 248 tests · 13.5 points below Logan County
- Radon levels in Hardin CountyEPA zone 1
43.3%at or above 4 pCi/L
Median 3.4 pCi/L · 67 tests · 30.3 points below Logan County
Logan County, Cities and towns
Cities and towns in Logan County
Logan County's population has barely moved since 2020: 46,302 residents on July 1, 2025 against 46,117 then, by the Census Bureau's estimates. That works out to 101 people per square mile of land. Its largest town, Bellefontaine, has 14,151 residents, 30.6% of the total. Testing is reported here more often than across the state: CDC's 755 reported tests for 2008 to 2017 come to 16.3 for every 1,000 residents (2025 estimate), against 8.3 for Ohio.
From Bellefontaine to Zanesfield, CDC publishes no figure by town: each reads Logan County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Bellefontaine | 14,151 | +0.3% | 30.6% |
| West Liberty | 1,756 | −0.4% | 3.8% |
| Russells Point | 1,323 | +0.1% | 2.9% |
| De Graff | 1,256 | +0.5% | 2.7% |
| Lakeview | 1,232 | +4.0% | 2.7% |
| Belle Center | 802 | −0.4% | 1.7% |
| West Mansfield | 766 | +1.2% | 1.7% |
| Quincy | 548 | +1.5% | 1.2% |
| Rushsylvania | 497 | +1.6% | 1.1% |
| Huntsville | 412 | +2.0% | 0.9% |
| Ridgewayextends beyond Logan County | 312 | −1.3% | Counted whole |
| Valley Hi | 229 | +0.9% | 0.5% |
- Zanesfield
13 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 Logan County is counted whole, so it has no share.
Logan County, Homes
Homes in Logan County
Of Logan County's 23,797 homes, 74% are detached houses, against 69% across Ohio; 10% are mobile homes. Half of its homes were built before 1973, close to Ohio's 1970: 39% date from before 1960 and 16% from 2000 or later. Owners live in 78% of the occupied homes (Ohio: 67%), so for most households a test and a fix are their own to order.
| Homes | Logan County | Ohio |
|---|---|---|
| Housing units | 23,797 | 5,271,573 |
| Detached houses | 74% | 69% |
| In buildings of 5 or more | 5% | 15% |
| Mobile homes | 10% | 4% |
| Built before 1960 | 39% | 38% |
| Built since 2000 | 16% | 16% |
| Middle year built | 1973 | 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.