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Locations and reports
Radon in Louisville, Kentucky
EPA puts Jefferson County, where Louisville is, in Zone 1, its highest radon zone, and 39.4% of its 6,590 reported radon tests (2008 to 2017, laboratory totals) were 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
39.4%
4.3 pts below KY
- Jefferson
- 39.4%
- Kentucky
- 43.7%
Jefferson, 29th of 69 in KY, 2008 to 2017
Median result
2.7pCi/L
Below action level
- Jefferson
- 2.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of Jefferson's tests, 2008 to 2017
Nearest county
47.5%
Bullitt, 18 miles
- Bullitt
- 47.5%
- Jefferson
- 39.4%
551 tests, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
Jefferson, where Louisville is
Tests reported
6,590
In Jefferson
- Jefferson
- 6,590
- Bullitt
- 551
Reported to CDC before any fix, 2008 to 2017
Read a result for Louisville
Starts at Jefferson County's median, 2.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.7 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. Jefferson County's median reported result, 2008 to 2017.
The data
Louisville, What is published
What is published for Louisville
Information:
Every figure for Louisville is a county's
Radon data is published by county, not by city, so for Louisville it is Jefferson County's: its EPA zone (Zone 1) and the 6,590 tests reported to CDC for 2008 to 2017, laboratory. Only a test tells you about one home.
Louisville covers 61.5 square miles of land, all of it in Jefferson County.
Louisville, Counties
The county Louisville lies in
MeasuredJefferson County's EPA zone and the figures CDC publishes for it, 2008 to 2017, laboratory.
Jefferson CountyZone 1Highest predicted potential
- 39.4%
- Reported tests at or above 4 pCi/L
- 2.7 pCi/L
- Median reported result
- 6,590 tests
- Tests reported to CDC
- None
- Yearly figures on file
Jefferson County ranks 29th of 69 Kentucky counties with 30 or more tests for that period, 4.3 points below the 43.7% pooled across Kentucky's counties, 3.7 points above the national pool of 35.7%.
The counties nearest Louisville with a CDC figure for 2008 to 2017, laboratory, measured from the middle of the city: Bullitt County (18 miles, 47.5% of 551 tests), Oldham County (20 miles, 37.1% of 803 tests) and Spencer County (26 miles, 31.3% of 166 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 31.3% to 68.4%; the farthest of them, Hardin County, is 38 miles away at 50.3%.
The directory lists 1 business with an address in Louisville, 1 for testing and 1 for mitigation. Kentucky's other cities with a page of their own: Lexington.
The counties around Louisville
By distance from the middle of Louisville; counties with 30 or more tests.
Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2008 to 2017, laboratory.
Louisville, Geology
The ground under Louisville
PredictedMost of the ground under Louisville is one class on USGS's geologic map: 96.2% of its land is high radon potential, with 3.2% moderate. 96.2% of it lies in the area the map calls New Albany-Chattanooga Shale, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| New Albany-Chattanooga Shale | Devonian/Mississippian Black shale. | High | 14 | 96.2% |
| Mississippian Plateau | Mississippian marine limestones, dolomites, marine sandstones, siltstones, and shales. | Moderate | 11 | 3.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Louisville beside its county and Kentucky
Louisville sits on more high-potential ground than Jefferson County as a whole: 96.2% of the city against 55.1% of the county. Louisville has more high-potential ground than Kentucky as a whole: 96.2% of its land against 18.2%.
The map rates the ground, not the air in any home.
Local help
Louisville, Professionals
Radon professionals listed in Louisville
Businesses whose listed city is Louisville, from the state registries and listings in the Radon411 directory, with the same business and certification status the directory shows.
Radon professionals listed in Louisville: 1 of 1
1 listing with Louisville as the city. See radon mitigation and testing in Louisville, or all radon professionals in Kentucky.
Louisville, Local resources
Local resources for Louisville
Who to ask in Kentucky: its radon program, test kits and professionals.
What it means
Louisville, Questions
Questions about radon in Louisville
What radon zone is Louisville in?
EPA's map puts Jefferson County, and with it Louisville, in Zone 1, the map's highest class: a predicted county average above 4 pCi/L.
What are radon levels in Louisville?
A high result is no surprise around Louisville: 39.4% of 6,590 tests reported from Jefferson County for 2008 to 2017 (laboratory totals) reached 4 pCi/L or more. The median reported result was 2.7 pCi/L.
Should I test my home in Louisville?
Yes. About 2,596 of the 6,590 tests reported from Jefferson County were at or above 4 pCi/L. That is below Kentucky's pooled 43.7%, and still not a reason to skip it, and ranks Jefferson County 29th of the 69 Kentucky counties with 30 or more tests. No map says which homes those are. How to test a home.
What ground is Louisville built on, as far as radon goes?
USGS's geologic map puts all of Louisville on one named area, "New Albany-Chattanooga Shale", rated high for radon potential, radon index 14.
Is radon higher in the counties around Louisville?
Some are and some are not. Against Jefferson County's 39.4%, 4 of the 8 nearest counties with a figure report more and 4 less, from Spencer County (31.3%, 26 miles off) to Meade County (68.4%, 31 miles off).
Who tests for or fixes radon in Louisville?
Radon411's directory has one business with an address in Louisville, listed for both testing and mitigation. Every entry names the public list it was taken from. Radon professionals in Louisville.
The answers use the published figures of Jefferson County, the county Louisville lies in.
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