Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Putnam County, Ohio
EPA puts Putnam County in Zone 2, its middle radon zone, and high results are common there: 59.6% of the 94 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
59.6%
7.3 pts above OH
- Putnam
- 59.6%
- Ohio
- 52.3%
94 tests, 2008 to 2017
Median result
4.8pCi/L
Action level reached
- Putnam
- 4.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
94
63rd of 79 by tests
- Putnam
- 94
- Franklin
- 16,142
Reported to CDC before any fix, 2008 to 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 Ohio
26 of 79
Middle half
- Putnam
- 59.6%
- Pickaway
- 81.4%
By share, of 79 with 30+ tests
Read a result for Putnam County
Starts at Putnam County's median, 4.8 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.8 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. Putnam County's median reported result, 2008 to 2017.
The data
Putnam County, At a glance
Putnam County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Putnam County is a
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 Putnam County, 2008 to 2017, laboratory
Under 2 pCi/L: 16%2 to 4 pCi/L: 24%4 pCi/L and above: 60%
Of 94 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 15 | 16.0% |
| 2 to 4 pCi/L | 23 | 24.5% |
| 4 pCi/L and above | 56 | 59.6% |
What these figures count
These are the 94 tests reported to CDC for Putnam 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).
Putnam County, Compared
Putnam County radon figures, compared
Calculated by Radon411More than half: 59.6% of the 94 radon tests reported to CDC for Putnam County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 26th of 79 Ohio counties with 30 or more tests for the same period. That is 7.3 points above the 52.3% pooled from 88 Ohio counties.
The median result, 4.8 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 30.9 pCi/L. The rest split 16.0% under 2 pCi/L and 24.5% from 2 to 4 (Ohio: 23.1% and 24.6%). The reported tests do not follow EPA's Zone 2 label for Putnam County (predicted average between 2 and 4 pCi/L): 59.6% of them reached 4 pCi/L, fewer than that label suggests.
1 of its 5 bordering counties with figures ran higher, led by Henry County at 61.8%; Wood County reported 45.5%. 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 Putnam County went from 76 tests (2005 to 2014) to 94 (2008 to 2017), the share going from 50.0% to 59.6%.
Nationally, every county with a figure for the same period pools to 35.7%; Putnam County sits 23.9 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Putnam County, Geology
The ground under Putnam County
PredictedUSGS's geologic map splits Putnam County: 67.7% of its land is high radon potential and 32.3% moderate. The map puts 67.7% of Putnam County in the area it calls Till Plains and 32.3% in Lake Plains. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 10, in the moderate band (9 to 11).
| 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 | 67.7% |
| Lake Plains | Glacial lake deposits, Devonian shale and limestone. | Moderate | 10 | 32.3% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Putnam County beside the ground around it
On high-potential ground Putnam County is close to Ohio as a whole: 67.7% of its land against 62.8%. Of the 7 counties that border it, 5 have more high-potential ground, Allen County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Putnam County, Local resources
Radon testing and mitigation in Putnam County
Listed radon businesses with an address in Putnam 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: Ottawa, Ottoville
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
Putnam County, Questions
Questions about radon in Putnam County
Are radon levels high in Putnam County?
Over the 2008 to 2017 laboratory totals, 59.6% of the radon tests reported to CDC for Putnam County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.8 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 25 reported a higher share; pooled, the state comes to 52.3%.
Which counties border Putnam County?
Putnam County borders 7 counties: Henry County, Allen County, Hancock County, Paulding County, Defiance County, Van Wert County and Wood County.
Products
Putnam County, Products
Testing a home in Putnam County
In Putnam County, 59.6% of 94 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 52.3% pooled across Ohio. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Putnam 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
RM-63Pro rechargeable radon monitor with a touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Putnam County, Bordering counties
Counties bordering Putnam County
Calculated by Radon411- Radon levels in Henry CountyEPA zone 2
61.8%at or above 4 pCi/L
Median 5.3 pCi/L · 34 tests · 2.2 points above Putnam County
- Radon levels in Allen CountyEPA zone 1
56.7%at or above 4 pCi/L
Median 5.0 pCi/L · 238 tests · 2.9 points below Putnam County
- Radon levels in Van Wert CountyEPA zone 1
53.8%at or above 4 pCi/L
Median 4.3 pCi/L · 26 tests · 5.8 points below Putnam County
- Radon levels in Defiance CountyEPA zone 2
48.6%at or above 4 pCi/L
Median 3.8 pCi/L · 70 tests · 11.0 points below Putnam County
- Radon levels in Hancock CountyEPA zone 1
46.2%at or above 4 pCi/L
Median 3.7 pCi/L · 1,382 tests · 13.4 points below Putnam County
- Radon levels in Wood CountyEPA zone 2
45.5%at or above 4 pCi/L
Median 3.5 pCi/L · 1,192 tests · 14.1 points below Putnam County
- Radon levels in Paulding CountyEPA zone 2
23.1%at or above 4 pCi/L
Median 3.2 pCi/L · 13 tests · 36.5 points below Putnam County
Putnam County, Cities and towns
Cities and towns in Putnam County
Putnam County's population has barely moved since 2020: 34,380 residents on July 1, 2025 against 34,392 then, by the Census Bureau's estimates. That works out to 71 people per square mile of land. No town dominates: Ottawa, the largest, has 4,437 residents, 12.9% of the total. Together its 15 incorporated places hold 46.3% of those residents; the other 53.7% live outside any of them. Reported testing is thin here: 94 tests over 2008 to 2017, or 2.7 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.
From Ottawa to Belmore, CDC publishes no figure by town: each reads Putnam County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Ottawa | 4,437 | −0.4% | 12.9% |
| Leipsic | 2,167 | −0.7% | 6.3% |
| Columbus Grove | 2,132 | −0.8% | 6.2% |
| Kalida | 1,481 | +1.4% | 4.3% |
| Pandora | 1,149 | −4.1% | 3.3% |
| Continental | 1,103 | −0.2% | 3.2% |
| Glandorf | 985 | +2.1% | 2.9% |
| Ottoville | 975 | +1.7% | 2.8% |
| Fort Jennings | 532 | +1.7% | 1.5% |
| West Leipsic | 218 | −1.8% | 0.6% |
| Dupont | 208 | −0.5% | 0.6% |
| Cloverdale | 170 | −1.2% | 0.5% |
- Gilboa
- Miller City
- Belmore
15 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).
Putnam County, Homes
Homes in Putnam County
Putnam County is a place of houses on their own lots: 88% of its 13,870 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1972, close to Ohio's 1970: 38% date from before 1960 and 14% from 2000 or later. Owners live in 86% of the occupied homes (Ohio: 67%), so for most households a test and a fix are their own to order.
| Homes | Putnam County | Ohio |
|---|---|---|
| Housing units | 13,870 | 5,271,573 |
| Detached houses | 88% | 69% |
| In buildings of 5 or more | 3% | 15% |
| Mobile homes | 4% | 4% |
| Built before 1960 | 38% | 38% |
| Built since 2000 | 14% | 16% |
| Middle year built | 1972 | 1970 |
| Owner-occupied | 86% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.