Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in DeKalb County, Tennessee
EPA puts DeKalb County in Zone 2, its middle radon zone, and only 12 radon tests from it are on file with CDC (2022). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
31.7%
1.7 pts below TN
- DeKalb
- 31.7%
- Tennessee
- 33.4%
63 tests, 2007 to 2016
Median result
3.1pCi/L
Below action level
- DeKalb
- 3.1 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2007 to 2016
Tests reported
63
52nd of 77 by tests
- DeKalb
- 63
- Davidson
- 5,151
Reported to CDC before any fix, 2007 to 2016
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
37 of 77
Middle half
- DeKalb
- 31.7%
- Jefferson
- 58.6%
By share, of 77 with 30+ tests
Read a result for DeKalb County
Starts at DeKalb County's median, 3.1 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.1 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. DeKalb County's median reported result, 2007 to 2016.
The data
DeKalb County, At a glance
DeKalb County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
DeKalb County is a
USGS geologic potential: High across 63% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for DeKalb County, 2022
CDC holds 12 reported tests for DeKalb County in 2022, with a median of 59.2 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). DeKalb County beside the counties around it is how this page reads it.
What these figures count
Only 12 tests were reported to CDC for DeKalb County over 2022, 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: 2022. Measured data period: 2005 to 2022 (every CDC figure on file).
DeKalb County, Compared
DeKalb County radon figures, compared
Calculated by Radon411In DeKalb County, about 3 in 10 reported tests over the 2007 to 2016 laboratory totals (20 of 63) were at or above EPA's action level. Against the national pool of 35.8%, the gap is 4.1 points lower. Across 95 Tennessee counties pooled together, 33.4% of tests reached that level, so DeKalb County runs 1.7 points below its state.
The newest figure, in 2022, counts only 12 tests (100.0% at or above 4 pCi/L), too few to compare, so this reading uses the 63-test figure.
Of 6 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 13.0% (Cannon County) to 48.6% (White County). By share, DeKalb County is 37th of 77 Tennessee counties with 30 or more tests for the same period.
Half the tests came in under 3.1 pCi/L and half over it; the single highest reached 17.3 pCi/L. Below the action level, 23 tests (36.5%) came in under 2 pCi/L, against 42.3% statewide, and 20 tests (31.7%) fell between 2 and 4, against 24.3% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 31.7% share point the same way here. USGS geology rates 63% of the county's land high radon potential.
CDC's ten-year totals for DeKalb County went from 54 tests (2005 to 2014) to 59 (2008 to 2017), the share going from 31.5% to 30.5%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
DeKalb County, Geology
The ground under DeKalb County
PredictedUSGS's geologic map splits DeKalb County: 62.9% of its land is high radon potential and 37.1% moderate. The map puts 62.9% of DeKalb County in the area it calls Nashville Basin and 37.1% in Highland Rim. USGS gives the first a radon index of 14, 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 |
|---|---|---|---|---|
| Nashville Basin | Mississippian Limestone. | High | 14 | 62.9% |
| Highland Rim | Paleozoic sedimentary rocks (limestone, shale, chert, and dolostone). | Moderate | 11 | 37.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
DeKalb County beside the ground around it
DeKalb County has more high-potential ground than Tennessee as a whole: 62.9% of its land against 47.2%. Of the 6 counties that border it, 2 have more high-potential ground, Smith County the most at 100%.
The map rates the ground, not the air in any home.
Local help
DeKalb County, Local resources
Radon testing and mitigation in DeKalb 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
DeKalb County, Questions
Questions about radon in DeKalb County
Are radon levels high in DeKalb County?
In 2022, 100.0% of the radon tests reported to CDC for DeKalb County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 59.2 pCi/L. Of 77 Tennessee counties with 30 or more tests for the same period, 36 reported a higher share; pooled, the state comes to 33.4%.
Which counties border DeKalb County?
DeKalb County borders 6 counties: Cannon County, Smith County, Warren County, White County, Putnam County and Wilson County.
Products
DeKalb County, Products
Testing a home in DeKalb County
In DeKalb County, 31.7% of 63 tests reported to CDC over the 2007 to 2016 laboratory totals reached 4 pCi/L, against 33.4% pooled across Tennessee. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in DeKalb 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
MonitorSafetySiren
Pro4 plug-in radon detector with a display and alarm
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 48 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
DeKalb County, Bordering counties
Counties bordering DeKalb County
Calculated by Radon411- Radon levels in White CountyEPA zone 2
48.6%at or above 4 pCi/L
Median 3.9 pCi/L · 140 tests · 16.9 points above DeKalb County
- Radon levels in Smith CountyEPA zone 1
48.1%at or above 4 pCi/L
Median 3.2 pCi/L · 54 tests · 16.4 points above DeKalb County
- Radon levels in Putnam CountyEPA zone 2
36.6%at or above 4 pCi/L
Median 2.7 pCi/L · 309 tests · 4.9 points above DeKalb County
- Radon levels in Warren CountyEPA zone 2
35.9%at or above 4 pCi/L
Median 2.9 pCi/L · 142 tests · 4.2 points above DeKalb County
- Radon levels in Wilson CountyEPA zone 1
19.4%at or above 4 pCi/L
Median 1.7 pCi/L · 863 tests · 12.3 points below DeKalb County
- Radon levels in Cannon CountyEPA zone 2
13.0%at or above 4 pCi/L
Median 1.5 pCi/L · 54 tests · 18.7 points below DeKalb County
DeKalb County, Cities and towns
Cities and towns in DeKalb County
DeKalb County is growing: the Census Bureau puts it at 21,873 residents on July 1, 2025, up 8.4% from 20,186 in 2020. That works out to 72 people per square mile of land. Its largest town, Smithville, has 5,620 residents, 25.7% of the total. Together its 4 incorporated places hold 33.3% of those residents; the other 66.7% live outside any of them. CDC's 63 reported tests for 2007 to 2016 work out to 2.9 per 1,000 residents (2025 estimate), close to Tennessee's 4.0.
From Smithville to Liberty, CDC publishes no figure by town: each reads DeKalb County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Smithville | 5,620 | +11.4% | 25.7% |
| Alexandria | 951 | +3.9% | 4.3% |
| Dowelltown | 370 | +7.6% | 1.7% |
| Liberty | 342 | +2.4% | 1.6% |
4 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).
DeKalb County, Homes
Homes in DeKalb County
DeKalb County is a place of houses on their own lots: 75% of its 10,033 homes are detached single-family houses, against 68% across Tennessee. Half of its homes were built before 1984, close to Tennessee's 1986: 11% date from before 1960 and 26% from 2000 or later. 69% of occupied homes are lived in by their owner (Tennessee: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | DeKalb County | Tennessee |
|---|---|---|
| Housing units | 10,033 | 3,095,472 |
| Detached houses | 75% | 68% |
| In buildings of 5 or more | 3% | 14% |
| Mobile homes | 14% | 8% |
| Built before 1960 | 11% | 18% |
| Built since 2000 | 26% | 29% |
| Middle year built | 1984 | 1986 |
| Owner-occupied | 69% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.