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
Locations and reports
Radon Levels in Madison County, Alabama
EPA puts Madison County in Zone 1, its highest radon zone, and 25.2% of its 5,178 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
25.2%
3.3 pts above AL
- Madison
- 25.2%
- Alabama
- 21.9%
5,178 tests, 2008 to 2017
Median result
1.9pCi/L
Below action level
- Madison
- 1.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
5,178
Most tested in Alabama
- Madison
- 5,178
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 Alabama
3 of 27
Top quarter
- Madison
- 25.2%
- Colbert
- 36.2%
By share, of 27 with 30+ tests
Read a result for Madison County
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
Madison County, At a glance
Madison County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Madison County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Madison County, 2008 to 2017, laboratory
Under 2 pCi/L: 50%2 to 4 pCi/L: 25%4 pCi/L and above: 25%
Of 5,178 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 2,590 | 50.0% |
| 2 to 4 pCi/L | 1,284 | 24.8% |
| 4 pCi/L and above | 1,304 | 25.2% |
What these figures count
These are the 5,178 tests reported to CDC for Madison 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).
Madison County, Compared
Madison County radon figures, compared
Calculated by Radon411Madison County's 5,178 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.9 pCi/L and a maximum of 261.0 pCi/L, and 25.2% reached 4 pCi/L. Alabama as a whole (65 Alabama counties, pooled) comes to 21.9%: 3.3 points lower than here.
Among its state's counties it ranks 3rd of 27 Alabama counties with 30 or more tests for the same period. Statewide for the same period, Colbert County reported the highest share (36.2%) and Baldwin County the lowest (0.0%).
Below the action level, 2,590 tests (50.0%) came in under 2 pCi/L, against 54.3% statewide, and 1,284 tests (24.8%) fell between 2 and 4, against 23.8% statewide. CDC's ten-year totals for Madison County went from 5,777 tests (2005 to 2014) to 5,178 (2008 to 2017), the share going from 25.6% to 25.2%.
EPA's 1993 zone map puts Madison County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land high radon potential.
Next door, the shares run from 10.1% in Limestone County to 25.6% in Franklin County, TN, with Lincoln County, TN, Jackson County and Marshall County below Madison County.
CDC also counts 62 tests taken after mitigation in Madison County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Madison County, Geology
The ground under Madison County
PredictedUSGS's geologic map puts all of Madison County'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.
Madison County beside the ground around it
Madison County has more high-potential ground than Alabama as a whole: 100% of its land against 14.3%. Of the 6 counties that border it, none has as large a share of high-potential ground; Limestone County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Madison County, Local resources
Radon testing and mitigation in Madison County
- Alabama Radon ProgramAlabama Radon Program, run by Alabama Department of Public Health, answers questions about testing, mitigation and the rules in Alabama.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
- See the Alabama directoryNo professionals are listed in Alabama yet. The state program can point you to registered testers and mitigators.
What Alabama's program says
- Phone
- (334) 290-6244
What it means
Madison County, Questions
Questions about radon in Madison County
Are radon levels high in Madison County?
Over the 2008 to 2017 laboratory totals, 25.2% of the radon tests reported to CDC for Madison County, Alabama were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.9 pCi/L. Of 27 Alabama counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 21.9%.
Which counties border Madison County?
Madison County borders 6 counties: Morgan County, AL, Limestone County, AL, Marshall County, AL, Jackson County, AL, Lincoln County, TN and Franklin County, TN.
Products
Madison County, Products
Testing a home in Madison County
In Madison County, 25.2% of 5,178 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 21.9% pooled across Alabama. In Zone 1 the year-round level in Madison 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
Wave Radon battery smart radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- App only
Method: Alpha spectrometry
Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Madison County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Madison County
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Madison County, Bordering counties
Counties bordering Madison County
Calculated by Radon411- Radon levels in Franklin County, TNEPA zone 3
25.6%at or above 4 pCi/L
Median 2.1 pCi/L · 266 tests · 0.4 points above Madison County
- Radon levels in Lincoln County, TNEPA zone 1
20.8%at or above 4 pCi/L
Median 1.9 pCi/L · 149 tests · 4.4 points below Madison County
- Radon levels in Jackson County, ALEPA zone 1
17.5%at or above 4 pCi/L
Median 1.5 pCi/L · 223 tests · 7.7 points below Madison County
- Radon levels in Marshall County, ALEPA zone 2
15.1%at or above 4 pCi/L
Median 1.3 pCi/L · 199 tests · 10.1 points below Madison County
- Radon levels in Morgan County, ALEPA zone 1
14.6%at or above 4 pCi/L
Median 1.4 pCi/L · 453 tests · 10.6 points below Madison County
- Radon levels in Limestone County, ALEPA zone 1
10.1%at or above 4 pCi/L
Median 1.3 pCi/L · 674 tests · 15.1 points below Madison County
Madison County, Cities and towns
Cities and towns in Madison County
Madison County is growing: the Census Bureau puts it at 433,516 residents on July 1, 2025, up 11.0% from 390,515 in 2020. That works out to 541 people per square mile of land. Huntsville, the largest place on its list (233,627 residents in all), extends beyond Madison County, so no share of the total is worked out for it. Testing is reported here more often than across the state: CDC's 5,178 reported tests for 2008 to 2017 come to 11.9 for every 1,000 residents (2025 estimate), against 2.4 for Alabama.
From Huntsville to Gurley, CDC publishes no figure by town: each reads Madison County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Huntsvilleextends beyond Madison County | 233,627 | +8.0% | Counted whole |
| Madisonextends beyond Madison County | 67,968 | +18.8% | Counted whole |
| Triana | 5,244 | +74.6% | 1.2% |
| Owens Cross Roads | 3,334 | +25.7% | 0.8% |
| New Hope | 3,054 | +5.6% | 0.7% |
| Gurley | 853 | +1.2% | 0.2% |
Places in Madison County with a city page: 1 of 1
6 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 Madison County is counted whole, so it has no share.
Madison County, Homes
Homes in Madison County
Of Madison County's 174,709 homes, 72% are detached houses, against 69% across Alabama; 17% are in buildings of five or more homes. Half of its homes were built before 1991, close to Alabama's 1985: 9% date from before 1960 and 36% from 2000 or later. 69% of occupied homes are lived in by their owner (Alabama: 70%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Madison County | Alabama |
|---|---|---|
| Housing units | 174,709 | 2,316,192 |
| Detached houses | 72% | 69% |
| In buildings of 5 or more | 17% | 12% |
| Mobile homes | 4% | 13% |
| Built before 1960 | 9% | 16% |
| Built since 2000 | 36% | 27% |
| Middle year built | 1991 | 1985 |
| Owner-occupied | 69% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.