Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Ascension Parish, Louisiana
EPA puts Ascension Parish in Zone 3, its lowest radon zone, and most reported tests there come back low, though 0.0% of 522 (2021) 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
0.0%
3.9 pts below LA
- Ascension Parish
- 0.0%
- Louisiana
- 3.9%
522 tests, 2021
Median result
0.2pCi/L
Below action level
- Ascension Parish
- 0.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2021
Tests reported
522
Most tested in Louisiana
- Ascension Parish
- 522
Reported to CDC before any fix, 2021
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Louisiana
3 of 14
Top quarter
- Ascension Parish
- 0.0%
- Caddo Parish
- 20.1%
By share, of 14 with 30+ tests
Read a result for Ascension Parish
Starts at Ascension Parish's median, 0.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 0.2 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. Ascension Parish's median reported result, 2021.
The data
Ascension Parish, At a glance
Ascension Parish at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Ascension Parish, 2021
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 0.0% |
| 2016 | 0.0% |
| 2017 | 0.0% |
| 2018 | 0.0% |
| 2021 | 0.0% |
2021: 0.0%. Across these years the share ran from 0.0% to 0.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 522 tests reported to CDC for Ascension Parish over 2021, many from homes being sold or already suspected of a problem: they describe the parish's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2021. Measured data period: 2005 to 2021 (every CDC figure on file).
Ascension Parish, Compared
Ascension Parish radon figures, compared
Calculated by Radon411Only 0 of 522 radon tests reported for Ascension Parish in 2021 reached 4 pCi/L (0.0%). The median result, 0.2 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 1.5 pCi/L.
Across 21 Louisiana counties pooled together, 3.9% of tests reached that level, so Ascension Parish runs 3.9 points below its state. Against the national pool of 24.4%, the gap is 24.4 points lower. Its place in the state: 3rd of 14 Louisiana counties with 30 or more tests for the same period.
Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 0.0% share point the same way here. East Baton Rouge Parish, the one bordering county with a figure for the same period, reported 0.0%.
Below the action level, 522 tests (100.0%) came in under 2 pCi/L, against 92.3% statewide, and 0 tests (0.0%) fell between 2 and 4, against 3.8% statewide. USGS geology rates 100% of the county's land low radon potential.
The busiest year on file was 2021, with 522 tests reported; the quietest, 2017, had 6.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Ascension Parish, Geology
The ground under Ascension Parish
PredictedUSGS's geologic map puts all of Ascension Parish's mapped land in one class: low radon potential. The map puts 92.9% of Ascension Parish in the area it calls Delta and 7.1% in Floodplain. USGS gives the first a radon index of 6 and the second 7, both in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Delta | Alluvium and marsh. | Low | 6 | 92.9% |
| Floodplain | Alluvium, marsh, silt, and clay. | Low | 7 | 7.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Ascension Parish beside the ground around it
Neither Ascension Parish nor Louisiana as a whole has any land USGS rates above low potential. None of the 6 parishes that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Ascension Parish, Local resources
Radon testing and mitigation in Ascension Parish
- Louisiana's radon programLouisiana Department of Environmental QualityLouisiana's radon program answers questions about testing, mitigation and the rules in Louisiana.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 Louisiana directoryNo professionals are listed in Louisiana yet. The state program can point you to registered testers and mitigators.
What it means
Ascension Parish, Questions
Questions about radon in Ascension Parish
Are radon levels high in Ascension Parish?
In 2021, 0.0% of the radon tests reported to CDC for Ascension Parish, Louisiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.2 pCi/L. Of 14 Louisiana counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 3.9%.
Which counties border Ascension Parish?
Ascension Parish borders 6 parishes: St. James Parish, Livingston Parish, St. John the Baptist Parish, Assumption Parish, East Baton Rouge Parish and Iberville Parish.
Products
Ascension Parish, Products
Testing a home in Ascension Parish
In Ascension Parish, 0.0% of 522 tests reported to CDC in 2021 reached 4 pCi/L, against 3.9% pooled across Louisiana. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Ascension Parish.
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
Monitor
RM-65 rechargeable radon detector with a color screen and alarm
- 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
Ascension Parish, Bordering parishes
Parishes bordering Ascension Parish
Calculated by Radon411- Radon levels in East Baton Rouge ParishEPA zone 3
0.0%at or above 4 pCi/L
Median 0.4 pCi/L · 420 tests · 0.0 points above Ascension Parish
- Radon levels in St. James ParishEPA zone 3
No CDC figure for 2021; its page reads it against its own neighbours.
- Radon levels in Livingston ParishEPA zone 3
No CDC figure for 2021; its page reads it against its own neighbours.
No CDC figure for 2021; its page reads it against its own neighbours.
- Radon levels in Assumption ParishEPA zone 3
No CDC figure for 2021; its page reads it against its own neighbours.
- Radon levels in Iberville ParishEPA zone 3
No CDC figure for 2021; its page reads it against its own neighbours.
Ascension Parish, Cities and towns
Cities and towns in Ascension Parish
Ascension Parish is growing: the Census Bureau puts it at 135,105 residents on July 1, 2025, up 6.4% from 126,975 in 2020. That works out to 466 people per square mile of land. No town dominates: Gonzales, the largest, has 13,930 residents, 10.3% of the total. Together its 3 incorporated places hold 16.8% of those residents; the other 83.2% live outside any of them. Testing is reported here more often than across the state: CDC's 522 reported tests for 2021 come to 3.9 for every 1,000 residents (2025 estimate), against 0.7 for Louisiana.
From Gonzales to Sorrento, CDC publishes no figure by town: each reads Ascension Parish's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Gonzales | 13,930 | +14.7% | 10.3% |
| Donaldsonville | 7,094 | +4.8% | 5.3% |
| Sorrento | 1,622 | +5.6% | 1.2% |
3 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).
Ascension Parish, Homes
Homes in Ascension Parish
Of Ascension Parish's 50,971 homes, 74% are detached houses, against 65% across Louisiana; 17% are mobile homes. Much of Ascension Parish is recent building: 55% of its homes have gone up since 2000 and the middle year built is 2002, against 1982 for Louisiana. Owners live in 83% of the occupied homes (Louisiana: 67%), so for most households a test and a fix are their own to order.
| Homes | Ascension Parish | Louisiana |
|---|---|---|
| Housing units | 50,971 | 2,094,002 |
| Detached houses | 74% | 65% |
| In buildings of 5 or more | 6% | 11% |
| Mobile homes | 17% | 13% |
| Built before 1960 | 6% | 19% |
| Built since 2000 | 55% | 27% |
| Middle year built | 2002 | 1982 |
| Owner-occupied | 83% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.