Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in Caldwell County, Kentucky
EPA puts Caldwell County in Zone 2, its middle radon zone, and only 20 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
36.1%
Christian County
- Christian
- 36.1%
- Hopkins
- 9.5%
3 of 6 neighbours have 30+ tests, 2008 to 2017
Nearest county
9.5%
Hopkins County, 21 miles
- Hopkins
- 9.5%
- Kentucky
- 43.7%
Share at 4+ pCi/L, 42 tests, 2008 to 2017
Ground above low
100.0%
5.7 pts above Kentucky
- Caldwell
- 100.0%
- Kentucky
- 94.3%
Share of land USGS rates moderate or high potential
Tests reported
23
Too few for a share
- Caldwell
- 23
- Needed
- 30
2006 to 2015, laboratory
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Caldwell 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
Caldwell County, At a glance
Caldwell County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Caldwell 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 Caldwell County, 2008 to 2017, laboratory
CDC holds 20 reported tests for Caldwell County over the 2008 to 2017 laboratory totals, with a median of 3.7 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Caldwell County beside the counties around it is how this page reads it.
What these figures count
Only 20 tests were reported to CDC for Caldwell County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Caldwell County, Compared
Caldwell County radon figures, compared
Calculated by Radon411CDC's largest figure for Caldwell County rests on 23 tests over the 2006 to 2015 laboratory totals, 8 of them at or above 4 pCi/L, so each test moves its share by 4.3 points and no rank or comparison is drawn from it. Results reached as high as 15.5 pCi/L, with a middle value of 2.9 pCi/L.
Of the counties bordering it, 3 have a figure over the 2008 to 2017 laboratory totals: Christian County reported the largest share at or above 4 pCi/L, 36.1%, and Hopkins County the smallest, 9.5%, with Trigg County at 22.2% between. Farther out, Marshall County (31 miles away) at 10.6%, Todd County (44 miles away) at 17.7% and Henderson County (48 miles away) at 24.1% have figures too. Pooled across 120 Kentucky counties, 43.7% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Meade County reported the highest share (68.4%) and Hopkins County the lowest (9.5%). EPA's 1993 map puts Caldwell County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Caldwell County, Geology
The ground under Caldwell County
PredictedUSGS's geologic map puts all of Caldwell County's mapped land in one class: moderate radon potential. The map puts 70.4% of Caldwell County in the area it calls Mississippian Plateau and 29.6% in Western Coalfield. USGS gives the first a radon index of 11 and the second 9, both in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Mississippian Plateau | Mississippian marine limestones, dolomites, marine sandstones, siltstones, and shales. | Moderate | 11 | 70.4% |
| Western Coalfield | Limestones, shale, siltstone, and coal beds. | Moderate | 9 | 29.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Caldwell County beside the ground around it
Across Kentucky 18.2% of the land is rated high; none of Caldwell County's is. Of the 6 counties that border it, none has as large a share of moderate-potential ground; Christian County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Caldwell County, Local resources
Radon testing and mitigation in Caldwell County
- Kentucky's radon programKentucky Board of Radon SafetyKentucky's radon program answers questions about testing, mitigation and the rules in Kentucky.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Kentucky8 professionals are listed in Kentucky.
What Kentucky's program says
- Phone
- 502-782-2782
- Radon@ky.gov
What it means
Caldwell County, Questions
Questions about radon in Caldwell County
Are radon levels high in Caldwell County?
Over the 2008 to 2017 laboratory totals, 40.0% of the radon tests reported to CDC for Caldwell County, Kentucky were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.7 pCi/L. Of the counties bordering it, 3 have a figure over the 2008 to 2017 laboratory totals: Christian County reported the largest share at or above 4 pCi/L, 36.1%, and Hopkins County the smallest, 9.5%, with Trigg County at 22.2% between.
Which counties border Caldwell County?
Caldwell County borders 6 counties: Lyon County, Crittenden County, Hopkins County, Trigg County, Christian County and Webster County.
Products
Caldwell County, Products
Testing a home in Caldwell County
No CDC figure names Caldwell County; the nearest county with one, Hopkins County (21 miles away), reported 9.5% 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. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Caldwell County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-1011S rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Caldwell County, Bordering counties
Counties bordering Caldwell County
Calculated by Radon411- Radon levels in Christian CountyEPA zone 2
36.1%at or above 4 pCi/L
Median 3.2 pCi/L · 72 tests
- Radon levels in Lyon CountyEPA zone 2
35.7%at or above 4 pCi/L
Median 2.5 pCi/L · 14 tests
- Radon levels in Crittenden CountyEPA zone 2
25.0%at or above 4 pCi/L
Median 1.6 pCi/L · 8 tests
- Radon levels in Trigg CountyEPA zone 2
22.2%at or above 4 pCi/L
Median 2.4 pCi/L · 45 tests
- Radon levels in Webster CountyEPA zone 2
12.5%at or above 4 pCi/L
Median 2.0 pCi/L · 8 tests
- Radon levels in Hopkins CountyEPA zone 2
9.5%at or above 4 pCi/L
Median 1.7 pCi/L · 42 tests
Caldwell County, Cities and towns
Cities and towns in Caldwell County
Caldwell County's population has barely moved since 2020: 12,609 residents on July 1, 2025 against 12,642 then, by the Census Bureau's estimates. That works out to 37 people per square mile of land. Its largest town, Princeton, has 6,168 residents, 48.9% of the total. Reported testing is thin here: 23 tests over 2006 to 2015, or 1.8 for every 1,000 residents (2025 estimate), where Kentucky as a whole comes to 5.0.
From Princeton to Fredonia, CDC publishes no figure by town: each reads Caldwell County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Princeton | 6,168 | −1.5% | 48.9% |
| Dawson Springsextends beyond Caldwell County | 2,231 | −9.0% | Counted whole |
| Fredonia | 375 | +0.5% | 3.0% |
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). A place that extends beyond Caldwell County is counted whole, so it has no share.
Caldwell County, Homes
Homes in Caldwell County
Caldwell County is a place of houses on their own lots: 81% of its 6,085 homes are detached single-family houses, against 68% across Kentucky. The homes are older than Kentucky's as a whole: half were built before 1974 (1982 for Kentucky), and 31% date from before 1960. 72% of occupied homes are lived in by their owner (Kentucky: 68%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Caldwell County | Kentucky |
|---|---|---|
| Housing units | 6,085 | 2,010,655 |
| Detached houses | 81% | 68% |
| In buildings of 5 or more | 2% | 12% |
| Mobile homes | 11% | 11% |
| Built before 1960 | 31% | 22% |
| Built since 2000 | 21% | 24% |
| Middle year built | 1974 | 1982 |
| Owner-occupied | 72% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.