Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in St. Clair County, Alabama
EPA puts St. Clair County in Zone 2, its middle radon zone, and most reported tests there come back low, though 14.0% of 93 (2008 to 2017, laboratory totals) reached 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
14.0%
7.9 pts below AL
- St. Clair
- 14.0%
- Alabama
- 21.9%
93 tests, 2008 to 2017
Median result
1.2pCi/L
Below action level
- St. Clair
- 1.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
93
15th of 27 by tests
- St. Clair
- 93
- Madison
- 5,178
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Alabama
16 of 27
Middle half
- St. Clair
- 14.0%
- Colbert
- 36.2%
By share, of 27 with 30+ tests
Read a result for St. Clair County
Starts at St. Clair County's median, 1.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.2 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. St. Clair County's median reported result, 2008 to 2017.
The data
St. Clair County, At a glance
St. Clair County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
St. Clair 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 St. Clair County, 2008 to 2017, laboratory
Under 2 pCi/L: 69%2 to 4 pCi/L: 17%4 pCi/L and above: 14%
Of 93 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 64 | 68.8% |
| 2 to 4 pCi/L | 16 | 17.2% |
| 4 pCi/L and above | 13 | 14.0% |
What these figures count
These are the 93 tests reported to CDC for St. Clair 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).
St. Clair County, Compared
St. Clair County radon figures, compared
Calculated by Radon411St. Clair County reports fewer high tests than Alabama overall. 14.0% of its 93 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 7.9 points below the 21.9% pooled from 65 Alabama counties.
Ordered from highest share down, it comes 16th of 27 Alabama counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; St. Clair County sits 21.7 points below it.
Next door, the shares run from 10.7% in Jefferson County to 19.6% in Etowah County, with Blount County, Shelby County and Jefferson County below St. Clair County. Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 14.0% share point the same way here.
Half the tests came in under 1.2 pCi/L and half over it; the single highest reached 12.1 pCi/L. The rest split 68.8% under 2 pCi/L and 17.2% from 2 to 4 (Alabama: 54.3% and 23.8%).
CDC's ten-year totals for St. Clair County went from 71 tests (2005 to 2014) to 93 (2008 to 2017), the share going from 15.5% to 14.0%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
St. Clair County, Geology
The ground under St. Clair County
PredictedUSGS's geologic map puts all of St. Clair County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Valley and Ridge, to which USGS gives a radon index of 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Valley and Ridge | Chattanooga black shale, Cambrian-Ordovician limestone and sandstone. | Moderate | 9 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
St. Clair County beside the ground around it
Across Alabama 14.3% of the land is rated high; none of St. Clair County's is. Of the 6 counties that border it, 3 have more high-potential ground, Talladega County the most at 54.8%.
The map rates the ground, not the air in any home.
Local help
St. Clair County, Local resources
Radon testing and mitigation in St. Clair 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
St. Clair County, Questions
Questions about radon in St. Clair County
Are radon levels high in St. Clair County?
Over the 2008 to 2017 laboratory totals, 14.0% of the radon tests reported to CDC for St. Clair County, Alabama were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.2 pCi/L. Of 27 Alabama counties with 30 or more tests for the same period, 15 reported a higher share; pooled, the state comes to 21.9%.
Which counties border St. Clair County?
St. Clair County borders 6 counties: Talladega County, Blount County, Calhoun County, Etowah County, Jefferson County and Shelby County.
Products
St. Clair County, Products
Testing a home in St. Clair County
In St. Clair County, 14.0% of 93 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 21.9% pooled across Alabama. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in St. Clair County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
MonitorAEGTEST
HOUND-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
St. Clair County, Bordering counties
Counties bordering St. Clair County
Calculated by Radon411- Radon levels in Etowah CountyEPA zone 2
19.6%at or above 4 pCi/L
Median 1.4 pCi/L · 56 tests · 5.6 points above St. Clair County
- Radon levels in Calhoun CountyEPA zone 1
18.9%at or above 4 pCi/L
Median 1.4 pCi/L · 238 tests · 4.9 points above St. Clair County
- Radon levels in Talladega CountyEPA zone 1
18.5%at or above 4 pCi/L
Median 1.6 pCi/L · 124 tests · 4.5 points above St. Clair County
- Radon levels in Blount CountyEPA zone 2
13.6%at or above 4 pCi/L
Median 2.0 pCi/L · 44 tests · 0.4 points below St. Clair County
- Radon levels in Shelby CountyEPA zone 2
11.3%at or above 4 pCi/L
Median 1.3 pCi/L · 373 tests · 2.7 points below St. Clair County
- Radon levels in Jefferson CountyEPA zone 2
10.7%at or above 4 pCi/L
Median 1.2 pCi/L · 912 tests · 3.3 points below St. Clair County
St. Clair County, Cities and towns
Cities and towns in St. Clair County
St. Clair County is growing: the Census Bureau puts it at 98,206 residents on July 1, 2025, up 7.1% from 91,703 in 2020. That works out to 155 people per square mile of land. Trussville, the largest place on its list (27,273 residents in all), extends beyond St. Clair County, so no share of the total is worked out for it. Reported testing is thin here: 93 tests over 2008 to 2017, or 0.9 for every 1,000 residents (2025 estimate), where Alabama as a whole comes to 2.4.
From Trussville to Steele, CDC publishes no figure by town: each reads St. Clair County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Trussvilleextends beyond St. Clair County | 27,273 | +4.0% | Counted whole |
| Pell City | 14,320 | +10.4% | 14.6% |
| Moody | 13,559 | +2.5% | 13.8% |
| Leedsextends beyond St. Clair County | 12,831 | +3.6% | Counted whole |
| Margaret | 7,149 | +36.5% | 7.3% |
| Odenville | 6,023 | +22.1% | 6.1% |
| Springville | 5,597 | +16.6% | 5.7% |
| Argoextends beyond St. Clair County | 4,376 | −0.6% | Counted whole |
| Ashville | 2,412 | +2.2% | 2.5% |
| Riverside | 2,312 | +3.6% | 2.4% |
| Vincentextends beyond St. Clair County | 2,045 | +3.1% | Counted whole |
| Ragland | 1,710 | +1.2% | 1.7% |
- Steele
13 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond St. Clair County is counted whole, so it has no share.
St. Clair County, Homes
Homes in St. Clair County
Of St. Clair County's 38,667 homes, 72% are detached houses, against 69% across Alabama; 22% are mobile homes. Much of St. Clair County is recent building: 44% of its homes have gone up since 2000 and the middle year built is 1997, against 1985 for Alabama. Owners live in 82% of the occupied homes (Alabama: 70%), so for most households a test and a fix are their own to order.
| Homes | St. Clair County | Alabama |
|---|---|---|
| Housing units | 38,667 | 2,316,192 |
| Detached houses | 72% | 69% |
| In buildings of 5 or more | 3% | 12% |
| Mobile homes | 22% | 13% |
| Built before 1960 | 7% | 16% |
| Built since 2000 | 44% | 27% |
| Middle year built | 1997 | 1985 |
| Owner-occupied | 82% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.