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 Montgomery County, Ohio
EPA puts Montgomery County in Zone 1, its highest radon zone, and high results are common there: 50.3% of the 2,922 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
50.3%
2.0 pts below OH
- Montgomery
- 50.3%
- Ohio
- 52.3%
2,922 tests, 2008 to 2017
Median result
4.0pCi/L
Action level reached
- Montgomery
- 4.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
2,922
9th of 79 by tests
- Montgomery
- 2,922
- 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
46 of 79
Middle half
- Montgomery
- 50.3%
- Pickaway
- 81.4%
By share, of 79 with 30+ tests
Read a result for Montgomery County
Starts at Montgomery County's median, 4.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 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. Montgomery County's median reported result, 2008 to 2017.
The data
Montgomery County, At a glance
Montgomery County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Montgomery 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 Montgomery County, 2008 to 2017, laboratory
Under 2 pCi/L: 24%2 to 4 pCi/L: 26%4 pCi/L and above: 50%
Of 2,922 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 683 | 23.4% |
| 2 to 4 pCi/L | 769 | 26.3% |
| 4 pCi/L and above | 1,470 | 50.3% |
What these figures count
These are the 2,922 tests reported to CDC for Montgomery 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).
Montgomery County, Compared
Montgomery County radon figures, compared
Calculated by Radon411More than half: 50.3% of the 2,922 radon tests reported to CDC for Montgomery County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 46th of 79 Ohio counties with 30 or more tests for the same period. That is 2.0 points below the 52.3% pooled from 88 Ohio counties.
The median result, 4.0 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 72.2 pCi/L. The rest split 23.4% under 2 pCi/L and 26.3% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 50.3% share point the same way here.
All 7 of its bordering counties with figures ran higher, led by Miami County at 65.2%; the lowest of them, Warren County, reported 52.5%. 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 Montgomery County went from 4,279 tests (2005 to 2014) to 2,922 (2008 to 2017), the share going from 47.2% to 50.3%.
Nationally, every county with a figure for the same period pools to 35.7%; Montgomery County sits 14.6 points above it. CDC also counts 51 tests taken after mitigation in Montgomery 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.
Montgomery County, Geology
The ground under Montgomery County
PredictedUSGS's geologic map puts all of Montgomery 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.
Montgomery County beside the ground around it
Montgomery County has more high-potential ground than Ohio as a whole: 100% of its land against 62.8%. Of the 7 counties that border it, none has as large a share of high-potential ground; Clark County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Montgomery County, Local resources
Radon testing and mitigation in Montgomery County
Listed radon businesses with an address in Montgomery 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: Dayton, Huber Heights, Miamisburg, Springboro, Englewood
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
Montgomery County, Questions
Questions about radon in Montgomery County
Are radon levels high in Montgomery County?
Over the 2008 to 2017 laboratory totals, 50.3% of the radon tests reported to CDC for Montgomery County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.0 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 45 reported a higher share; pooled, the state comes to 52.3%.
Which counties border Montgomery County?
Montgomery County borders 7 counties: Warren County, Preble County, Greene County, Butler County, Miami County, Clark County and Darke County.
Products
Montgomery County, Products
Testing a home in Montgomery County
In Montgomery County, 50.3% of 2,922 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 Montgomery 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
RM-65 rechargeable radon detector with a color screen and alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 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
Montgomery County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Montgomery County
Explore
Montgomery County, Bordering counties
Counties bordering Montgomery County
Calculated by Radon411- Radon levels in Miami CountyEPA zone 1
65.2%at or above 4 pCi/L
Median 6.1 pCi/L · 690 tests · 14.9 points above Montgomery County
- Radon levels in Darke CountyEPA zone 1
63.7%at or above 4 pCi/L
Median 5.6 pCi/L · 270 tests · 13.4 points above Montgomery County
- Radon levels in Preble CountyEPA zone 1
62.7%at or above 4 pCi/L
Median 5.5 pCi/L · 212 tests · 12.4 points above Montgomery County
- Radon levels in Greene CountyEPA zone 1
58.6%at or above 4 pCi/L
Median 4.9 pCi/L · 2,602 tests · 8.3 points above Montgomery County
- Radon levels in Clark CountyEPA zone 1
57.5%at or above 4 pCi/L
Median 4.9 pCi/L · 1,447 tests · 7.2 points above Montgomery County
- Radon levels in Butler CountyEPA zone 1
54.3%at or above 4 pCi/L
Median 4.4 pCi/L · 1,953 tests · 4.0 points above Montgomery County
- Radon levels in Warren CountyEPA zone 1
52.5%at or above 4 pCi/L
Median 4.2 pCi/L · 2,512 tests · 2.2 points above Montgomery County
Montgomery County, Cities and towns
Cities and towns in Montgomery County
Montgomery County's population has barely moved since 2020: 539,598 residents on July 1, 2025 against 537,115 then, by the Census Bureau's estimates. Packed into its land, that is 1,170 people per square mile. Dayton, the largest place on its list (136,688 residents in all), extends beyond Montgomery County, so no share of the total is worked out for it. Reported testing is thin here: 2,922 tests over 2008 to 2017, or 5.4 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.
From Dayton to Verona, CDC publishes no figure by town: each reads Montgomery County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Daytonextends beyond Montgomery County | 136,688 | −0.5% | Counted whole |
| Ketteringextends beyond Montgomery County | 57,396 | −0.7% | Counted whole |
| Huber Heightsextends beyond Montgomery County | 43,905 | +1.1% | Counted whole |
| Centervilleextends beyond Montgomery County | 25,194 | +2.9% | Counted whole |
| Riverside | 24,706 | +0.9% | 4.6% |
| Trotwood | 23,190 | +0.5% | 4.3% |
| Miamisburg | 20,414 | +2.6% | 3.8% |
| Springboroextends beyond Montgomery County | 19,606 | +2.5% | Counted whole |
| Vandalia | 15,014 | −0.6% | 2.8% |
| Clayton | 13,397 | +0.8% | 2.5% |
| Englewood | 13,343 | −0.8% | 2.5% |
| West Carrollton | 12,963 | −0.8% | 2.4% |
Places in Montgomery County with a city page: 1 of 1
- Oakwood
- Union (part)
- Moraine
- Brookville
- Germantown
- Carlisle (part)
- New Lebanon
- Farmersville
- Phillipsburg
- Verona (part)
22 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 Montgomery County is counted whole, so it has no share.
Montgomery County, Homes
Homes in Montgomery County
Of Montgomery County's 252,475 homes, 67% are detached houses, against 69% across Ohio; 16% are in buildings of five or more homes. Half of its homes were built before 1966, close to Ohio's 1970: 40% date from before 1960 and 9% from 2000 or later. 62% of occupied homes are lived in by their owner (Ohio: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Montgomery County | Ohio |
|---|---|---|
| Housing units | 252,475 | 5,271,573 |
| Detached houses | 67% | 69% |
| In buildings of 5 or more | 16% | 15% |
| Mobile homes | 1% | 4% |
| Built before 1960 | 40% | 38% |
| Built since 2000 | 9% | 16% |
| Middle year built | 1966 | 1970 |
| Owner-occupied | 62% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.