Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Humphreys County, Tennessee
EPA puts Humphreys County in Zone 1, its highest radon zone, and only 2 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
23.8%
9.5 pts below TN
- Humphreys
- 23.8%
- Tennessee
- 33.3%
105 tests, 2008 to 2017
Median result
2.0pCi/L
Below action level
- Humphreys
- 2.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
105
45th of 80 by tests
- Humphreys
- 105
- Davidson
- 5,592
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 Tennessee
52 of 80
Middle half
- Humphreys
- 23.8%
- Jefferson
- 56.8%
By share, of 80 with 30+ tests
Read a result for Humphreys County
Starts at Humphreys County's median, 2.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.0 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Humphreys County's median reported result, 2008 to 2017.
The data
Humphreys County, At a glance
Humphreys County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Humphreys County in
USGS geologic potential: High across 58% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Humphreys County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2022 | 0.0% |
| 2023 | 0.0% |
2023: 0.0%. Across these years the share ran from 0.0% to 0.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 2 tests were reported to CDC for Humphreys County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Humphreys County, Compared
Humphreys County radon figures, compared
Calculated by Radon411Humphreys County's 105 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.0 pCi/L and a maximum of 29.0 pCi/L, and 23.8% reached 4 pCi/L. Tennessee as a whole (95 Tennessee counties, pooled) comes to 33.3%: 9.5 points higher than here.
The newest figure, in 2023, counts only 2 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 105-test figure.
Among its state's counties it ranks 52nd of 80 Tennessee counties with 30 or more tests for the same period. Statewide for the same period, Jefferson County reported the highest share (56.8%) and Chester County the lowest (0.0%).
Below the action level, 51 tests (48.6%) came in under 2 pCi/L, against 42.4% statewide, and 29 tests (27.6%) fell between 2 and 4, against 24.3% statewide. The busiest year on file was 2022, with 6 tests reported; the quietest, 2023, had 2.
EPA's 1993 zone map puts Humphreys County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 58% of the county's land high radon potential.
Next door, the shares run from 26.3% in Dickson County to 35.0% in Hickman County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Humphreys County, Geology
The ground under Humphreys County
PredictedUSGS's geologic map splits Humphreys County: 58.4% of its land is high radon potential and 41.6% moderate. The map puts 58.4% of Humphreys County in the area it calls Cherty Highland and 41.6% in Highland Rim. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Cherty Highland | Cherty dolostone. | High | 12 | 58.4% |
| Highland Rim | Paleozoic sedimentary rocks (limestone, shale, chert, and dolostone). | Moderate | 11 | 41.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Humphreys County beside the ground around it
Humphreys County has more high-potential ground than Tennessee as a whole: 58.4% of its land against 47.2%. Of the 5 counties that border it, 3 have more high-potential ground, Perry County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Humphreys County, Local resources
Radon testing and mitigation in Humphreys 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
Humphreys County, Questions
Questions about radon in Humphreys County
Are radon levels high in Humphreys County?
In 2023, 0.0% of the radon tests reported to CDC for Humphreys County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of 80 Tennessee counties with 30 or more tests for the same period, 51 reported a higher share; pooled, the state comes to 33.3%.
Which counties border Humphreys County?
Humphreys County borders 5 counties: Benton County, Houston County, Hickman County, Dickson County and Perry County.
Products
Humphreys County, Products
Testing a home in Humphreys County
In Humphreys County, 23.8% of 105 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 33.3% pooled across Tennessee. In Zone 1 the year-round level in Humphreys 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
MonitorForensics Detectors
FD-65-RADON rechargeable radon detector with a color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Humphreys County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Humphreys County
Explore
Humphreys County, Bordering counties
Counties bordering Humphreys County
Calculated by Radon411- Radon levels in Hickman CountyEPA zone 1
35.0%at or above 4 pCi/L
Median 2.2 pCi/L · 120 tests · 11.2 points above Humphreys County
- Radon levels in Benton CountyEPA zone 2
33.3%at or above 4 pCi/L
Median 2.0 pCi/L · 30 tests · 9.5 points above Humphreys County
- Radon levels in Perry CountyEPA zone 1
32.5%at or above 4 pCi/L
Median 2.0 pCi/L · 40 tests · 8.7 points above Humphreys County
- Radon levels in Houston CountyEPA zone 2
28.6%at or above 4 pCi/L
Median 2.8 pCi/L · 14 tests · 4.8 points above Humphreys County
- Radon levels in Dickson CountyEPA zone 2
26.3%at or above 4 pCi/L
Median 2.1 pCi/L · 209 tests · 2.5 points above Humphreys County
Humphreys County, Cities and towns
Cities and towns in Humphreys County
The Census Bureau estimates 19,646 residents in Humphreys County for July 1, 2025, 648 more than in 2020 (+3.4%). That works out to 37 people per square mile of land. Its largest town, Waverly, has 4,430 residents, 22.5% of the total. Together its 3 incorporated places hold 41.1% of those residents; the other 58.9% live outside any of them. CDC's 105 reported tests for 2008 to 2017 work out to 5.3 per 1,000 residents (2025 estimate), close to Tennessee's 4.2.
From Waverly to McEwen, CDC publishes no figure by town: each reads Humphreys County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Waverly | 4,430 | +3.0% | 22.5% |
| New Johnsonville | 1,849 | +2.5% | 9.4% |
| McEwen | 1,790 | +8.2% | 9.1% |
3 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).
Humphreys County, Homes
Homes in Humphreys County
Humphreys County is a place of houses on their own lots: 76% of its 8,868 homes are detached single-family houses, against 68% across Tennessee. The homes are older than Tennessee's as a whole: half were built before 1978 (1986 for Tennessee), and 20% date from before 1960. Owners live in 80% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.
| Homes | Humphreys County | Tennessee |
|---|---|---|
| Housing units | 8,868 | 3,095,472 |
| Detached houses | 76% | 68% |
| In buildings of 5 or more | 5% | 14% |
| Mobile homes | 17% | 8% |
| Built before 1960 | 20% | 18% |
| Built since 2000 | 19% | 29% |
| Middle year built | 1978 | 1986 |
| Owner-occupied | 80% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.