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 Miami County, Ohio
EPA puts Miami County in Zone 1, its highest radon zone, and high results are common there: 65.2% of the 690 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
65.2%
12.9 pts above OH
- Miami
- 65.2%
- Ohio
- 52.3%
690 tests, 2008 to 2017
Median result
6.1pCi/L
Action level reached
- Miami
- 6.1 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
690
31st of 79 by tests
- Miami
- 690
- 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
14 of 79
Top quarter
- Miami
- 65.2%
- Pickaway
- 81.4%
By share, of 79 with 30+ tests
Read a result for Miami County
Starts at Miami County's median, 6.1 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 6.1 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. Miami County's median reported result, 2008 to 2017.
The data
Miami County, At a glance
Miami County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Miami 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 Miami County, 2008 to 2017, laboratory
Under 2 pCi/L: 15%2 to 4 pCi/L: 20%4 pCi/L and above: 65%
Of 690 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 104 | 15.1% |
| 2 to 4 pCi/L | 136 | 19.7% |
| 4 pCi/L and above | 450 | 65.2% |
What these figures count
These are the 690 tests reported to CDC for Miami 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).
Miami County, Compared
Miami County radon figures, compared
Calculated by Radon411More than half: 65.2% of the 690 radon tests reported to CDC for Miami County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 14th of 79 Ohio counties with 30 or more tests for the same period. That is 12.9 points above the 52.3% pooled from 88 Ohio counties.
The median result, 6.1 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 181.0 pCi/L. The rest split 15.1% under 2 pCi/L and 19.7% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 65.2% share point the same way here.
1 of its 5 bordering counties with figures ran higher, led by Champaign County at 71.1%; Montgomery County reported 50.3%. 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 Miami County went from 917 tests (2005 to 2014) to 690 (2008 to 2017), the share going from 60.3% to 65.2%.
Nationally, every county with a figure for the same period pools to 35.7%; Miami County sits 29.5 points above it. CDC also counts 41 tests taken after mitigation in Miami 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.
Miami County, Geology
The ground under Miami County
PredictedUSGS's geologic map puts all of Miami 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.
Miami County beside the ground around it
Miami 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; Champaign County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Miami County, Local resources
Radon testing and mitigation in Miami County
Listed radon businesses with an address in Miami 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: Huber Heights, Troy, Tipp City
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
Miami County, Questions
Questions about radon in Miami County
Are radon levels high in Miami County?
Over the 2008 to 2017 laboratory totals, 65.2% of the radon tests reported to CDC for Miami County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.1 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 13 reported a higher share; pooled, the state comes to 52.3%.
Which counties border Miami County?
Miami County borders 5 counties: Shelby County, Darke County, Champaign County, Clark County and Montgomery County.
Products
Miami County, Products
Testing a home in Miami County
In Miami County, 65.2% of 690 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 Miami 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
MonitorAEGTEST
HOUND-3786 rechargeable radon monitor with a 3.5-inch color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Ion chamber
First reading: Within 10 minutes
Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Miami County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Miami County
Explore
Miami County, Bordering counties
Counties bordering Miami County
Calculated by Radon411- Radon levels in Champaign CountyEPA zone 1
71.1%at or above 4 pCi/L
Median 6.8 pCi/L · 596 tests · 5.9 points above Miami County
- Radon levels in Darke CountyEPA zone 1
63.7%at or above 4 pCi/L
Median 5.6 pCi/L · 270 tests · 1.5 points below Miami County
- Radon levels in Shelby CountyEPA zone 1
60.1%at or above 4 pCi/L
Median 5.2 pCi/L · 248 tests · 5.1 points below Miami County
- Radon levels in Clark CountyEPA zone 1
57.5%at or above 4 pCi/L
Median 4.9 pCi/L · 1,447 tests · 7.7 points below Miami County
- Radon levels in Montgomery CountyEPA zone 1
50.3%at or above 4 pCi/L
Median 4.0 pCi/L · 2,922 tests · 14.9 points below Miami County
Miami County, Cities and towns
Cities and towns in Miami County
The Census Bureau estimates 112,634 residents in Miami County for July 1, 2025, 3,660 more than in 2020 (+3.4%). That works out to 277 people per square mile of land. Huber Heights, the largest place on its list (43,905 residents in all), extends beyond Miami County, so no share of the total is worked out for it. CDC's 690 reported tests for 2008 to 2017 work out to 6.1 per 1,000 residents (2025 estimate), close to Ohio's 8.3.
From Huber Heights to Ludlow Falls, CDC publishes no figure by town: each reads Miami County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Huber Heightsextends beyond Miami County | 43,905 | +1.1% | Counted whole |
| Troy | 27,344 | +3.6% | 24.3% |
| Piqua | 21,064 | +3.2% | 18.7% |
| Tipp City | 10,644 | +3.4% | 9.5% |
| Unionextends beyond Miami County | 7,177 | +4.0% | Counted whole |
| West Milton | 4,871 | +3.6% | 4.3% |
| Covington | 2,635 | +3.2% | 2.3% |
| Bradfordextends beyond Miami County | 1,814 | +1.1% | Counted whole |
| Pleasant Hill | 1,270 | +3.2% | 1.1% |
| Fletcher | 469 | +3.8% | 0.4% |
| Laura | 412 | +3.8% | 0.4% |
| Casstown | 277 | +2.6% | 0.2% |
Places in Miami County with a city page: 1 of 1
- Potsdam
- Ludlow Falls
14 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 Miami County is counted whole, so it has no share.
Miami County, Homes
Homes in Miami County
Miami County is a place of houses on their own lots: 80% of its 47,028 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1970, close to Ohio's 1970: 37% date from before 1960 and 17% from 2000 or later. 73% 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 | Miami County | Ohio |
|---|---|---|
| Housing units | 47,028 | 5,271,573 |
| Detached houses | 80% | 69% |
| In buildings of 5 or more | 7% | 15% |
| Mobile homes | 1% | 4% |
| Built before 1960 | 37% | 38% |
| Built since 2000 | 17% | 16% |
| Middle year built | 1970 | 1970 |
| Owner-occupied | 73% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.