Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Assumption Parish, Louisiana
EPA puts Assumption Parish in Zone 3, its lowest radon zone, and most reported tests there come back low, though 0.0% of 102 (2022) 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%
0.4 pts below LA
- Assumption Parish
- 0.0%
- Louisiana
- 0.4%
102 tests, 2022
Median result
0.2pCi/L
Below action level
- Assumption Parish
- 0.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2022
Tests reported
102
8th of 9 by tests
- Assumption Parish
- 102
- Caddo Parish
- 486
Reported to CDC before any fix, 2022
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
2 of 9
Top quarter
- Assumption Parish
- 0.0%
- Caddo Parish
- 1.9%
By share, of 9 with 30+ tests
Read a result for Assumption Parish
Starts at Assumption 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. Assumption Parish's median reported result, 2022.
The data
Assumption Parish, At a glance
Assumption 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 Assumption Parish, 2022
Under 2 pCi/L: 100%2 to 4 pCi/L: 0%4 pCi/L and above: 0%
Of 102 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 102 | 100.0% |
| 2 to 4 pCi/L | 0 | 0.0% |
| 4 pCi/L and above | 0 | 0.0% |
What these figures count
These are the 102 tests reported to CDC for Assumption Parish over 2022, 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. Measured data period: 2022.
Assumption Parish, Compared
Assumption Parish radon figures, compared
Calculated by Radon411Only 0 of 102 radon tests reported for Assumption Parish in 2022 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 0.5 pCi/L.
Across 12 Louisiana counties pooled together, 0.4% of tests reached that level, so Assumption Parish runs 0.4 points below its state. Against the national pool of 23.9%, the gap is 23.9 points lower. Its place in the state: 2nd of 9 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.
Below the action level, 102 tests (100.0%) came in under 2 pCi/L, against 98.1% statewide, and 0 tests (0.0%) fell between 2 and 4, against 1.5% statewide. USGS geology rates 100% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Assumption Parish, Geology
The ground under Assumption Parish
PredictedUSGS's geologic map puts all of Assumption Parish's mapped land in one class: low radon potential. All of it lies in the area the map calls Delta, to which USGS gives a radon index of 6, 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 | 99.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Assumption Parish beside the ground around it
Neither Assumption Parish nor Louisiana as a whole has any land USGS rates above low potential. None of the 8 parishes that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Assumption Parish, Local resources
Radon testing and mitigation in Assumption 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
Assumption Parish, Questions
Questions about radon in Assumption Parish
Are radon levels high in Assumption Parish?
In 2022, 0.0% of the radon tests reported to CDC for Assumption Parish, Louisiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.2 pCi/L. Of 9 Louisiana counties with 30 or more tests for the same period, 1 reported a higher share; pooled, the state comes to 0.4%.
Which counties border Assumption Parish?
Assumption Parish borders 8 parishes: St. James Parish, St. Mary Parish, Ascension Parish, Iberville Parish, Terrebonne Parish, Iberia Parish, Lafourche Parish and St. Martin Parish.
Products
Assumption Parish, Products
Testing a home in Assumption Parish
In Assumption Parish, 0.0% of 102 tests reported to CDC in 2022 reached 4 pCi/L, against 0.4% 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 Assumption 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
Wave Radon battery smart radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- App only
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Assumption Parish, Bordering parishes
Parishes bordering Assumption Parish
Calculated by Radon411parishes bordering Assumption Parish: 1 of 8
Assumption Parish, Cities and towns
Cities and towns in Assumption Parish
Assumption Parish has been losing residents: from 20,962 in 2020 to 19,720 on July 1, 2025, a fall of 5.9% by the Census Bureau's estimates. That works out to 57 people per square mile of land. Napoleonville, its one incorporated place, has 500 residents, 2.5% of the total. Testing is reported here more often than across the state: CDC's 102 reported tests for 2022 come to 5.2 for every 1,000 residents (2025 estimate), against 0.4 for Louisiana.
Napoleonville is the one incorporated place here; CDC publishes no figure by town, so it reads Assumption Parish's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Napoleonville | 500 | −7.6% | 2.5% |
One incorporated place, 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).
Assumption Parish, Homes
Homes in Assumption Parish
Of Assumption Parish's 10,039 homes, 62% are detached houses, against 65% across Louisiana; 34% are mobile homes. Half of its homes were built before 1982, close to Louisiana's 1982: 20% date from before 1960 and 24% from 2000 or later. Owners live in 86% of the occupied homes (Louisiana: 67%), so for most households a test and a fix are their own to order.
| Homes | Assumption Parish | Louisiana |
|---|---|---|
| Housing units | 10,039 | 2,094,002 |
| Detached houses | 62% | 65% |
| In buildings of 5 or more | 1% | 11% |
| Mobile homes | 34% | 13% |
| Built before 1960 | 20% | 19% |
| Built since 2000 | 24% | 27% |
| Middle year built | 1982 | 1982 |
| Owner-occupied | 86% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.