Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Grundy County, Tennessee
EPA puts Grundy County in Zone 3, its lowest radon zone, and only 18 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
Highest bordering
36.9%
Warren County
- Warren
- 36.9%
- Coffee
- 16.5%
5 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
20.7%
Sequatchie County, 18 miles
- Sequatchie
- 20.7%
- Tennessee
- 33.3%
Share at 4+ pCi/L, 58 tests, 2008 to 2017
Ground above low
31.0%
38.5 pts below Tennessee
- Grundy
- 31.0%
- Tennessee
- 69.5%
Share of land USGS rates moderate or high potential
Tests reported
29
Too few for a share
- Grundy
- 29
- Needed
- 30
2008 to 2017, laboratory
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for Grundy County
Starts at EPA's action level
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.
The data
Grundy County, At a glance
Grundy County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 69% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Grundy County, 2022
Median reported resultHighest reported result
0.5 pCi/L0.8 pCi/L
| Year | Median reported result | Highest reported result | Share of tests at or above 4 pCi/L |
|---|---|---|---|
| 2022 | 0.5 pCi/L | 0.8 pCi/L | 0.0% |
| 2023 | No data | No data | No data |
What these figures count
Only 18 tests were reported to CDC for Grundy 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 2023 (every CDC figure on file).
Grundy County, Compared
Grundy County radon figures, compared
Calculated by Radon411CDC's largest figure for Grundy County rests on 29 tests over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 3.4 points and no rank or comparison is drawn from it. Results reached as high as 3.7 pCi/L, with a middle value of 1.0 pCi/L.
Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Warren County reported the largest share at or above 4 pCi/L, 36.9%, and Coffee County the smallest, 16.5%, with Marion County at 28.4%, Franklin County at 25.6% and Sequatchie County at 20.7% between. Farther out, Bledsoe County (33 miles away) at 24.3%, Hamilton County (35 miles away) at 19.3% and Cannon County (35 miles away) at 10.7% have figures too. Pooled across 95 Tennessee counties, 33.3% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Jefferson County reported the highest share (56.8%) and Chester County the lowest (0.0%). EPA's 1993 map puts Grundy County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 69% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Grundy County, Geology
The ground under Grundy County
PredictedUSGS's geologic map splits Grundy County: 69.0% of its land is low radon potential and 0.8% high and 30.2% moderate. The map puts 69.0% of Grundy County in the area it calls Appalachian Plateau and 30.2% in Highland Rim, with one smaller area beside them. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Appalachian Plateau | Sandstone and shale. | Low | 8 | 69.0% |
| Highland Rim | Paleozoic sedimentary rocks (limestone, shale, chert, and dolostone). | Moderate | 11 | 30.2% |
| Interior Low Plateaus | Mississippian carbonate rocks and shales. | High | 12 | 0.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Grundy County beside the ground around it
Tennessee as a whole has more high-potential ground than Grundy County: 47.2% of its land, against 0.8% here. Of the 5 counties that border it, 3 have more high-potential ground, Marion County the most at 49.3%.
The map rates the ground, not the air in any home.
Local help
Grundy County, Local resources
Radon testing and mitigation in Grundy 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
Grundy County, Questions
Questions about radon in Grundy County
Are radon levels high in Grundy County?
In 2022, 0.0% of the radon tests reported to CDC for Grundy County, Tennessee were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.5 pCi/L. Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Warren County reported the largest share at or above 4 pCi/L, 36.9%, and Coffee County the smallest, 16.5%, with Marion County at 28.4%, Franklin County at 25.6% and Sequatchie County at 20.7% between.
Which counties border Grundy County?
Grundy County borders 5 counties: Marion County, Sequatchie County, Warren County, Coffee County and Franklin County.
Products
Grundy County, Products
Testing a home in Grundy County
No CDC figure names Grundy County; the nearest county with one, Sequatchie County (18 miles away), reported 20.7% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Grundy County.
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
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Grundy County, Bordering counties
Counties bordering Grundy County
Calculated by Radon411- Radon levels in Warren CountyEPA zone 2
36.9%at or above 4 pCi/L
Median 3.0 pCi/L · 149 tests
- Radon levels in Marion CountyEPA zone 2
28.4%at or above 4 pCi/L
Median 1.6 pCi/L · 74 tests
- Radon levels in Franklin CountyEPA zone 3
25.6%at or above 4 pCi/L
Median 2.1 pCi/L · 266 tests
- Radon levels in Sequatchie CountyEPA zone 3
20.7%at or above 4 pCi/L
Median 1.9 pCi/L · 58 tests
- Radon levels in Coffee CountyEPA zone 2
16.5%at or above 4 pCi/L
Median 1.3 pCi/L · 206 tests
Grundy County, Cities and towns
Cities and towns in Grundy County
The Census Bureau estimates 14,116 residents in Grundy County for July 1, 2025, 575 more than in 2020 (+4.2%). That works out to 39 people per square mile of land. No town dominates: Gruetli-Laager, the largest, has 1,786 residents, 12.7% of the total. Reported testing is thin here: 29 tests over 2008 to 2017, or 2.1 for every 1,000 residents (2025 estimate), where Tennessee as a whole comes to 4.2.
From Gruetli-Laager to Beersheba Springs, CDC publishes no figure by town: each reads Grundy County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Gruetli-Laager | 1,786 | +2.8% | 12.7% |
| Monteagleextends beyond Grundy County | 1,439 | +3.9% | Counted whole |
| Tracy City | 1,427 | +2.4% | 10.1% |
| Altamont | 1,203 | +7.7% | 8.5% |
| Coalmont | 823 | +3.7% | 5.8% |
| Palmer | 584 | +5.0% | 4.1% |
| Beersheba Springs | 457 | +5.8% | 3.2% |
7 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 Grundy County is counted whole, so it has no share.
Grundy County, Homes
Homes in Grundy County
Of Grundy County's 6,213 homes, 71% are detached houses, against 68% across Tennessee; 23% are mobile homes. Half of its homes were built before 1984, close to Tennessee's 1986: 19% date from before 1960 and 25% from 2000 or later. Owners live in 83% of the occupied homes (Tennessee: 67%), so for most households a test and a fix are their own to order.
| Homes | Grundy County | Tennessee |
|---|---|---|
| Housing units | 6,213 | 3,095,472 |
| Detached houses | 71% | 68% |
| In buildings of 5 or more | 2% | 14% |
| Mobile homes | 23% | 8% |
| Built before 1960 | 19% | 18% |
| Built since 2000 | 25% | 29% |
| Middle year built | 1984 | 1986 |
| Owner-occupied | 83% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.