Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in McNairy County, Tennessee
EPA puts McNairy County in Zone 2, its middle radon zone, and most reported tests there come back low, though 8.5% of 59 (2008 to 2017, laboratory totals) reached 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
8.5%
24.8 pts below TN
- McNairy
- 8.5%
- Tennessee
- 33.3%
59 tests, 2008 to 2017
Median result
1.0pCi/L
Below action level
- McNairy
- 1.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
59
55th of 80 by tests
- McNairy
- 59
- Davidson
- 5,592
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 Tennessee
73 of 80
Lowest quarter
- McNairy
- 8.5%
- Jefferson
- 56.8%
By share, of 80 with 30+ tests
Read a result for McNairy County
Starts at McNairy County's median, 1.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.0 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. McNairy County's median reported result, 2008 to 2017.
The data
McNairy County, At a glance
McNairy County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
McNairy County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for McNairy County, 2008 to 2017, laboratory
Under 2 pCi/L: 86%2 to 4 pCi/L: 5%4 pCi/L and above: 9%
Of 59 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 51 | 86.4% |
| 2 to 4 pCi/L | 3 | 5.1% |
| 4 pCi/L and above | 5 | 8.5% |
What these figures count
These are the 59 tests reported to CDC for McNairy 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).
McNairy County, Compared
McNairy County radon figures, compared
Calculated by Radon411McNairy County reports fewer high tests than Tennessee overall. 8.5% of its 59 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 24.8 points below the 33.3% pooled from 95 Tennessee counties.
Ordered from highest share down, it comes 73rd of 80 Tennessee counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; McNairy County sits 27.2 points below it.
Next door, the shares run from 0.0% in Chester County to 7.9% in Hardin County, with Hardin County and Chester County below McNairy County. The reported tests do not follow EPA's Zone 2 label for McNairy County (predicted average between 2 and 4 pCi/L): 8.5% of them reached 4 pCi/L, fewer than that label suggests.
Half the tests came in under 1.0 pCi/L and half over it; the single highest reached 6.0 pCi/L. The rest split 86.4% under 2 pCi/L and 5.1% from 2 to 4 (Tennessee: 42.4% and 24.3%).
CDC's ten-year totals for McNairy County went from 50 tests (2005 to 2014) to 59 (2008 to 2017), the share going from 8.0% to 8.5%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
McNairy County, Geology
The ground under McNairy County
PredictedMost of the ground under McNairy County is one class on USGS's geologic map: 99.7% of its land is moderate radon potential, with 0.3% low. 99.1% of it lies in the area the map calls East Coastal Plain, to which USGS gives a radon index of 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| East Coastal Plain | Cretaceous and younger marine and fluvial sand, clay, and marl. | Moderate | 9 | 99.1% |
| Pontotoc Ridge/Black Prairies | Glauconitic sand, clay, sandy limestone, micaceous chalk, and lime. | Moderate | 9 | 0.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
McNairy County beside the ground around it
Across Tennessee 47.2% of the land is rated high; none of McNairy County's is. Of the 4 counties that border it, 1 has more high-potential ground, Hardin County the most at 42.7%.
The map rates the ground, not the air in any home.
Local help
McNairy County, Local resources
Radon testing and mitigation in McNairy County
- Tennessee Radon ProgramTennessee Radon Program, run by Department of Environment & Conservation, offers free or discounted test kits, and answers questions about testing and mitigation in Tennessee.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The Tennessee Radon Program provides free radon test kits and information assistance to residents, while also providing training opportunities to radon professionals across the state.
- Compare kits
- Professionals in Tennessee1 professional is listed in Tennessee.
What Tennessee's program says
- Phone
- 1-800-232-1139
- TDEC.Radon@tn.gov
What it means
McNairy County, Questions
Questions about radon in McNairy County
Are radon levels high in McNairy County?
Over the 2008 to 2017 laboratory totals, 8.5% of the radon tests reported to CDC for McNairy County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.0 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 72 reported a higher share; pooled, the state comes to 33.3%.
Which counties border McNairy County?
McNairy County borders 4 counties: Alcorn County, MS, Chester County, TN, Hardin County, TN and Hardeman County, TN.
Products
McNairy County, Products
Testing a home in McNairy County
In McNairy County, 8.5% of 59 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in McNairy County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
McNairy County, Bordering counties
Counties bordering McNairy County
Calculated by Radon411- Radon levels in Hardeman County, TNEPA zone 3
20.0%at or above 4 pCi/L
Median 1.6 pCi/L · 5 tests · 11.5 points above McNairy County
- Radon levels in Hardin County, TNEPA zone 2
7.9%at or above 4 pCi/L
Median 1.0 pCi/L · 38 tests · 0.6 points below McNairy County
- Radon levels in Chester County, TNEPA zone 2
0.0%at or above 4 pCi/L
Median 1.1 pCi/L · 44 tests · 8.5 points below McNairy County
- Radon levels in Alcorn County, MSEPA zone 2
No CDC figure for 2008 to 2017; its page reads it against its own neighbours.
McNairy County, Cities and towns
Cities and towns in McNairy County
The Census Bureau estimates 26,236 residents in McNairy County for July 1, 2025, 368 more than in 2020 (+1.4%). That works out to 47 people per square mile of land. No town dominates: Selmer, the largest, has 4,575 residents, 17.4% of the total. Reported testing is thin here: 59 tests over 2008 to 2017, or 2.2 for every 1,000 residents (2025 estimate), where Tennessee as a whole comes to 4.2.
From Selmer to Enville, CDC publishes no figure by town: each reads McNairy County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Selmer | 4,575 | +2.3% | 17.4% |
| Adamsvilleextends beyond McNairy County | 2,081 | −0.1% | Counted whole |
| Eastview | 775 | +1.2% | 3.0% |
| Bethel Springs | 756 | +1.5% | 2.9% |
| Michie | 669 | +1.7% | 2.5% |
| Guys | 420 | +1.0% | 1.6% |
| Stantonville | 343 | +2.4% | 1.3% |
| Ramer | 327 | Level | 1.2% |
| Finger | 279 | +1.1% | 1.1% |
| Milledgevilleextends beyond McNairy County | 275 | +1.9% | Counted whole |
| Envilleextends beyond McNairy County | 189 | +2.2% | Counted whole |
11 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). A place that extends beyond McNairy County is counted whole, so it has no share.
McNairy County, Homes
Homes in McNairy County
McNairy County is a place of houses on their own lots: 79% of its 12,278 homes are detached single-family houses, against 68% across Tennessee. Half of its homes were built before 1983, close to Tennessee's 1986: 15% date from before 1960 and 22% from 2000 or later. Owners live in 79% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.
| Homes | McNairy County | Tennessee |
|---|---|---|
| Housing units | 12,278 | 3,095,472 |
| Detached houses | 79% | 68% |
| In buildings of 5 or more | 1% | 14% |
| Mobile homes | 17% | 8% |
| Built before 1960 | 15% | 18% |
| Built since 2000 | 22% | 29% |
| Middle year built | 1983 | 1986 |
| 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.