Locations and reports
Radon in Huntsville, Alabama
Huntsville lies in 3 counties, in EPA Zone 1; 81.2% of it is in Madison County, where 25.2% of 5,178 reported tests (2008 to 2017, laboratory totals) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so the only way to know your home's level is to test it.
Data checked By Radon411Methodology
Share at 4+ pCi/L
25.2%
3.3 pts above AL
- Madison
- 25.2%
- Alabama
- 21.9%
Madison, 3rd of 27 in AL, 2008 to 2017
Median result
1.9pCi/L
Below action level
- Madison
- 1.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of Madison's tests, 2008 to 2017
Highest county
25.2%
Madison
- Madison
- 25.2%
- Limestone
- 10.1%
3 counties, 3 with 30+ tests, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
Madison; Limestone Zone 1, Morgan Zone 1
Tests reported
5,178
In Madison
- Madison
- 5,178
- Limestone
- 674
Reported to CDC before any fix, 2008 to 2017
Read a result for Huntsville
Starts at Madison County's median, 1.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.9 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Madison County's median reported result, 2008 to 2017.
The data
Huntsville, What is published
What is published for Huntsville
Every figure for Huntsville is a county's
Radon data is published by county, not by city, and Huntsville reaches into 3 counties: Madison County, Limestone County and Morgan County. Each has its own EPA zone and its own CDC test figures, set side by side below and each labelled with its county. Only a test tells you about one home.
Huntsville covers 218 square miles of land across 3 counties: 81.2% in Madison County, 18.3% in Limestone County and 0.5% in Morgan County. About 233,627 people live there, 1,071 to the square mile.
Huntsville, Counties
Huntsville's counties, side by side
MeasuredEach county's own EPA zone and its own published CDC figures for 2008 to 2017, laboratory, the newest period any of them has. A county without a figure for that period is shown without one, never with a figure from another year.
- Madison County
- EPA zone
- Zone 1: Highest predicted potential
- At or above 4 pCi/L
- 25.2%
- Median result
- 1.9 pCi/L
- Tests reported
- 5,178 tests
- Annual years on file
- None
- Limestone County
- EPA zone
- Zone 1: Highest predicted potential
- At or above 4 pCi/L
- 10.1%
- Median result
- 1.3 pCi/L
- Tests reported
- 674 tests
- Annual years on file
- None
- Morgan County
- EPA zone
- Zone 1: Highest predicted potential
- At or above 4 pCi/L
- 14.6%
- Median result
- 1.4 pCi/L
- Tests reported
- 453 tests
- Annual years on file
- None
| County | EPA zone | Reported tests at or above 4 pCi/L | Median reported result | Tests reported | Annual years on file |
|---|---|---|---|---|---|
| Madison County | Zone 1: Highest predicted potential | 25.2% | 1.9 pCi/L | 5,178 tests | None |
| Limestone County | Zone 1: Highest predicted potential | 10.1% | 1.3 pCi/L | 674 tests | None |
| Morgan County | Zone 1: Highest predicted potential | 14.6% | 1.4 pCi/L | 453 tests | None |
Huntsville spans 3 counties, each with its own EPA zone and its own CDC figure: Madison County (Zone 1, 25.2% of 5,178 tests), Limestone County (Zone 1, 10.1% of 674 tests) and Morgan County (Zone 1, 14.6% of 453 tests).
Madison County ranks 3rd of 27 Alabama counties with 30 or more tests for that period, 3.3 points above the 21.9% pooled across Alabama's counties, 10.5 points below the national pool of 35.7%. Of the city's other counties, Limestone County reported 10.1% and Morgan County reported 14.6%.
The counties nearest Huntsville with a CDC figure for 2008 to 2017, laboratory, measured from the middle of the city: Marshall County (30 miles, 15.1% of 199 tests), Jackson County (37 miles, 17.5% of 223 tests) and Lawrence County (40 miles, 16.2% of 154 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 11.4% to 27.2%; the farthest of them, Lauderdale County, is 59 miles away at 27.2%.
No business in the directory gives Huntsville as its address; the Alabama list covers it.
Against Alabama and its other counties
Shares of tests people chose to run and report, by county (2008 to 2017, laboratory); the state's is its counties' counts added up, calculated by Radon411. Only a test measures a home.
The counties around Huntsville
By distance from the middle of Huntsville; counties with 30 or more tests.
The median reported pre-mitigation result for 2008 to 2017, laboratory was 1.9 pCi/L in Madison County, 1.3 pCi/L in Limestone County and 1.4 pCi/L in Morgan County.
Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2008 to 2017, laboratory.
Huntsville, Geology
The ground under Huntsville
PredictedUSGS's geologic map puts all of Huntsville's mapped land in one class: high radon potential. All of it lies in the area the map calls Interior Low Plateaus, to which USGS gives a radon index of 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Interior Low Plateaus | Mississippian carbonate rocks and shales. | High | 12 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Huntsville beside its counties and Alabama
All of Huntsville, like all of Madison County, is rated high. Huntsville has more high-potential ground than Alabama as a whole: 100% of its land against 14.3%.
The map rates the ground, not the air in any home.
Huntsville, Homes
Homes in Huntsville
Of Huntsville's 102,592 homes, 63% are detached houses, against 72% across Madison County; 25% are in buildings of five or more homes. Half of its homes were built before 1984, close to Madison County's 1991: 12% date from before 1960 and 30% from 2000 or later. 58% of occupied homes are lived in by their owner (Madison County: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Huntsville | Madison County | Alabama |
|---|---|---|---|
| Housing units | 102,592 | 174,709 | 2,316,192 |
| Detached houses | 63% | 72% | 69% |
| In buildings of 5 or more | 25% | 17% | 12% |
| Mobile homes | 1% | 4% | 13% |
| Built before 1960 | 12% | 9% | 16% |
| Built since 2000 | 30% | 36% | 27% |
| Middle year built | 1984 | 1991 | 1985 |
| Owner-occupied | 58% | 69% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.
Local help
Huntsville, Local resources
Local resources for Huntsville
Who to ask in Alabama: its radon program, test kits and professionals.
- Alabama Radon ProgramRun by Alabama Department of Public Health, phone (334) 290-6244.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 AlabamaRadon testers and mitigators in Alabama, each with how its listing was checked.
The program's own words on licensing are on the Alabama page.
What it means
Huntsville, Questions
Questions about radon in Huntsville
What radon zone is Huntsville in?
All 3 counties Huntsville reaches into (Madison County, Limestone County and Morgan County) are in Zone 1, the map's highest class: a predicted county average above 4 pCi/L. EPA zones counties, not cities, so that is the zone for every part of Huntsville.
What are radon levels in Huntsville?
A high result is no surprise around Huntsville: 25.2% of 5,178 tests reported from Madison County for 2008 to 2017 (laboratory totals) reached 4 pCi/L or more. The median reported result was 1.9 pCi/L. Limestone County reported 10.1% of 674 tests and Morgan County reported 14.6% of 453 tests; the counties are kept apart.
Should I test my home in Huntsville?
Yes. About 1,305 of the 5,178 tests reported from Madison County were at or above 4 pCi/L. That is above Alabama's pooled 21.9%, and ranks Madison County 3rd of the 27 Alabama counties with 30 or more tests. No map says which homes those are. How to test a home.
What ground is Huntsville built on, as far as radon goes?
USGS's geologic map puts all of Huntsville on one named area, "Interior Low Plateaus", rated high for radon potential, radon index 12.
Is radon higher in the counties around Huntsville?
Some are and some are not. Against Madison County's 25.2%, 1 of the 8 nearest counties with a figure report more and 7 less, from Cullman County (11.4%, 41 miles off) to Lauderdale County (27.2%, 59 miles off).
The answers use the published figures of Madison County, Limestone County and Morgan County, the counties Huntsville lies in.
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