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 Franklin County, Kentucky
EPA puts Franklin County in Zone 1, its highest radon zone, and high results are common there: 43.1% of the 810 radon tests reported to CDC (2008 to 2017, laboratory totals) came back at or above 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
43.1%
0.6 pts below KY
- Franklin
- 43.1%
- Kentucky
- 43.7%
810 tests, 2008 to 2017
Median result
3.3pCi/L
Below action level
- Franklin
- 3.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
810
7th of 69 by tests
- Franklin
- 810
- Jefferson
- 6,590
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 Kentucky
26 of 69
Middle half
- Franklin
- 43.1%
- Meade
- 68.4%
By share, of 69 with 30+ tests
Read a result for Franklin County
Starts at Franklin County's median, 3.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.3 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. Franklin County's median reported result, 2008 to 2017.
The data
Franklin County, At a glance
Franklin County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Franklin County in
USGS geologic potential: High across 67% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Franklin County, 2008 to 2017, laboratory
Under 2 pCi/L: 32%2 to 4 pCi/L: 25%4 pCi/L and above: 43%
Of 810 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 255 | 31.5% |
| 2 to 4 pCi/L | 206 | 25.4% |
| 4 pCi/L and above | 349 | 43.1% |
What these figures count
These are the 810 tests reported to CDC for Franklin 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).
Franklin County, Compared
Franklin County radon figures, compared
Calculated by Radon411In Franklin County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (349 of 810) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 7.4 points higher. Across 120 Kentucky counties pooled together, 43.7% of tests reached that level, so Franklin County runs 0.6 points below its state.
Of 6 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 25.2% (Anderson County) to 57.9% (Woodford County). By share, Franklin County is 26th of 69 Kentucky counties with 30 or more tests for the same period.
Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 60.6 pCi/L. Below the action level, 255 tests (31.5%) came in under 2 pCi/L, against 33.2% statewide, and 206 tests (25.4%) fell between 2 and 4, against 23.1% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 43.1% share point the same way here. USGS geology rates 67% of the county's land high radon potential. CDC also counts 30 tests taken after mitigation in Franklin County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Franklin County went from 489 tests (2005 to 2014) to 810 (2008 to 2017), the share going from 46.4% to 43.1%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Franklin County, Geology
The ground under Franklin County
PredictedUSGS's geologic map splits Franklin County: 66.8% of its land is high radon potential and 33.2% moderate. The map puts 66.8% of Franklin County in the area it calls Inner Bluegrass and 33.2% in Outer Bluegrass. USGS gives the first a radon index of 13, 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 |
|---|---|---|---|---|
| Inner Bluegrass | Ordovician limestones, dolomites and shales. | High | 13 | 66.8% |
| Outer Bluegrass | Ordovician-Devonian limestone and shale. | Moderate | 11 | 33.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Franklin County beside the ground around it
Franklin County has more high-potential ground than Kentucky as a whole: 66.8% of its land against 18.2%. Of the 6 counties that border it, 1 has more high-potential ground, Woodford County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Franklin County, Local resources
Radon testing and mitigation in Franklin 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
Franklin County, Questions
Questions about radon in Franklin County
Are radon levels high in Franklin County?
Over the 2008 to 2017 laboratory totals, 43.1% of the radon tests reported to CDC for Franklin County, Kentucky were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 69 Kentucky counties with 30 or more tests for the same period, 25 reported a higher share; pooled, the state comes to 43.7%.
Which counties border Franklin County?
Franklin County borders 6 counties: Woodford County, Anderson County, Scott County, Shelby County, Owen County and Henry County.
Products
Franklin County, Products
Testing a home in Franklin County
In Franklin County, 43.1% of 810 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 43.7% pooled across Kentucky. In Zone 1 the year-round level in Franklin 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
Monitor
RM-63Pro rechargeable radon monitor with a touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Franklin County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Franklin County
Explore
Franklin County, Bordering counties
Counties bordering Franklin County
Calculated by Radon411- Radon levels in Woodford CountyEPA zone 1
57.9%at or above 4 pCi/L
Median 4.9 pCi/L · 342 tests · 14.8 points above Franklin County
- Radon levels in Scott CountyEPA zone 1
46.9%at or above 4 pCi/L
Median 3.6 pCi/L · 875 tests · 3.8 points above Franklin County
- Radon levels in Shelby CountyEPA zone 2
37.6%at or above 4 pCi/L
Median 3.0 pCi/L · 407 tests · 5.5 points below Franklin County
- Radon levels in Henry CountyEPA zone 2
36.6%at or above 4 pCi/L
Median 3.2 pCi/L · 41 tests · 6.5 points below Franklin County
- Radon levels in Owen CountyEPA zone 2
36.2%at or above 4 pCi/L
Median 2.5 pCi/L · 58 tests · 6.9 points below Franklin County
- Radon levels in Anderson CountyEPA zone 2
25.2%at or above 4 pCi/L
Median 2.2 pCi/L · 226 tests · 17.9 points below Franklin County
Franklin County, Cities and towns
Cities and towns in Franklin County
The Census Bureau estimates 52,649 residents in Franklin County for July 1, 2025, 1,049 more than in 2020 (+2.0%). That works out to 253 people per square mile of land. Frankfort, its one incorporated place, has 28,657 residents, 54.4% of the total. Testing is reported here more often than across the state: CDC's 810 reported tests for 2008 to 2017 come to 15.4 for every 1,000 residents (2025 estimate), against 6.3 for Kentucky.
Frankfort is the one incorporated place here; CDC publishes no figure by town, so it reads Franklin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Frankfort | 28,657 | +0.1% | 54.4% |
One incorporated place, 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).
Franklin County, Homes
Homes in Franklin County
Of Franklin County's 24,082 homes, 66% are detached houses, against 68% across Kentucky; 15% are in buildings of five or more homes. Half of its homes were built before 1977, close to Kentucky's 1982: 24% date from before 1960 and 17% from 2000 or later. 64% 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 | Franklin County | Kentucky |
|---|---|---|
| Housing units | 24,082 | 2,010,655 |
| Detached houses | 66% | 68% |
| In buildings of 5 or more | 15% | 12% |
| Mobile homes | 5% | 11% |
| Built before 1960 | 24% | 22% |
| Built since 2000 | 17% | 24% |
| Middle year built | 1977 | 1982 |
| Owner-occupied | 64% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.