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Radon Levels in Lafourche Parish, Louisiana

EPA puts Lafourche Parish in Zone 3, its lowest radon zone, and only 3 radon tests from it are on file with CDC (2020). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

  • Highest bordering

    1.5%

    Jefferson Parish

    Jefferson Parish
    1.5%

    1 of 6 neighbours have 30+ tests, 2006 to 2015

  • Nearest county

    1.5%

    Jefferson Parish, 24 miles

    Jefferson Parish
    1.5%
    Louisiana
    2.8%

    Share at 4+ pCi/L, 67 tests, 2006 to 2015

  • Ground above low

    None

    Level with Louisiana

    Lafourche Parish
    0.0%
    Louisiana
    0.0%

    Share of land USGS rates moderate or high potential

  • Tests reported

    18

    Too few for a share

    Lafourche Parish
    18
    Needed
    30

    2019

  • EPA radon zone

    Zone 3

    Lower potential

    1. 1
    2. 2
    3. Zone 3

    1 highest, 3 lowest

    EPA predicts under 2 pCi/L indoors

Read a result for Lafourche Parish

Starts at EPA's action level

4.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.0 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.

The data

Lafourche Parish, At a glance

Lafourche Parish at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Lafourche Parish as a whole is an average indoor of less than 2 pCi/L (less than 75 Bq/m³). A low zone clears no address in it: homes above EPA's turn up in all three zones.

USGS geologic potential: Low across 95% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Lafourche Parish, 2020

Share of reported tests at or above 4 pCi/L, by year, Lafourche Parish
Share of reported tests at or above 4 pCi/L, by year, Lafourche Parish
YearShare of reported tests at or above 4 pCi/L
20140.0%
20180.0%
20190.0%
20200.0%

2020: 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

Only 3 tests were reported to CDC for Lafourche Parish over 2020, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the parish nor this house.

Measured: CDC tracking data. Figure above: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).

How to read these figures

Lafourche Parish, Compared

Lafourche Parish radon figures, compared

Calculated by Radon411

CDC's largest figure for Lafourche Parish rests on 18 tests in 2019, 0 of them at or above 4 pCi/L, so each test moves its share by 5.6 points and no rank or comparison is drawn from it. Results reached as high as 2.0 pCi/L, with a middle value of 1.2 pCi/L.

Jefferson Parish, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 1.5% of its tests at or above 4 pCi/L. Farther out, Tangipahoa Parish (73 miles away) at 0.0%, East Baton Rouge Parish (78 miles away) at 0.0% and Calcasieu Parish (182 miles away) at 0.0% have figures too. Pooled across 37 Louisiana counties, 2.8% of reported tests reached that level; across every county in the country with a figure, 36.3%.

Statewide for the same period, Jefferson Parish reported the highest share (1.5%) and Tangipahoa Parish the lowest (0.0%). EPA's 1993 map puts Lafourche Parish in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 95% of the county's land low radon potential.

Louisiana, the United States and the counties around Lafourche Parish, 2006 to 2015, laboratory
AreaTestsAt or above 4 pCi/LMedian
Louisiana, pooled37 counties, pooled4342.8%Not pooled
United States, pooled2,669 counties, pooled1,805,52836.3%Not pooled
Calcasieu Parishhighest in the state590.0%0.2 pCi/L
Tangipahoa Parishlowest in the state430.0%0.1 pCi/L
Jefferson Parish, LAborders it671.5%0.2 pCi/L
St. Charles Parish, LAborders it40.0%0.3 pCi/L
Terrebonne Parish, LAborders it150.0%0.5 pCi/L
The nearest Louisiana counties to Lafourche Parish with 30 or more tests, 2006 to 2015, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Jefferson Parish24 mi671.5%0.2 pCi/L
Tangipahoa Parish73 mi430.0%0.1 pCi/L
East Baton Rouge Parish78 mi480.0%0.6 pCi/L
Calcasieu Parish182 mi590.0%0.2 pCi/L
Lafourche Parish radon tests by year, against Louisiana's pooled share
YearTestsAt or above 4 pCi/LMedianHighestLouisiana, pooledChange from the row before
202030.0%0.8 pCi/L0.8 pCi/L0.8%Level
2019180.0%1.2 pCi/L2.0 pCi/L2.0%Level
201860.0%0.5 pCi/L0.6 pCi/L0.5%Level
201460.0%0.8 pCi/L0.8 pCi/L10.5%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Lafourche Parish, Geology

The ground under Lafourche Parish

Predicted

USGS's geologic map puts all of Lafourche Parish's mapped land in one class: low radon potential. 95.2% 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).

USGS's geologic areas under Lafourche Parish
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
DeltaAlluvium and marsh.Low695.2%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Lafourche Parish beside the ground around it

Neither Lafourche 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.

Share of land by USGS radon potential: Lafourche Parish, the 6 parishes bordering it and Louisiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Lafourche ParishZone 395.2%NoneNone
Jefferson ParishZone 384.8%NoneNone
St. Charles ParishZone 3100%NoneNone
Terrebonne ParishZone 382.9%NoneNone
St. John the Baptist ParishZone 3100%NoneNone
St. James ParishZone 3100%NoneNone
Assumption ParishZone 3100%NoneNone
Louisiana64 parishes, pooled by land areaVaries98.4%NoneNone

The map rates the ground, not the air in any home.

What it means

Lafourche Parish, Questions

Questions about radon in Lafourche Parish

Are radon levels high in Lafourche Parish?

In 2020, 0.0% of the radon tests reported to CDC for Lafourche Parish, Louisiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.8 pCi/L. Jefferson Parish, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 1.5% of its tests at or above 4 pCi/L.

Which counties border Lafourche Parish?

Lafourche Parish borders 6 parishes: Jefferson Parish, St. Charles Parish, Terrebonne Parish, St. John the Baptist Parish, St. James Parish and Assumption Parish.

Products

Lafourche Parish, Products

Testing a home in Lafourche Parish

No CDC figure names Lafourche Parish; the nearest county with one, Jefferson Parish (24 miles away), reported 1.5% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. 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 Lafourche Parish.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Lafourche Parish homes, compared

Explore

Lafourche Parish, Bordering parishes

Parishes bordering Lafourche Parish

Calculated by Radon411

Lafourche Parish, Cities and towns

Cities and towns in Lafourche Parish

About 95,505 people live in Lafourche Parish by the Census Bureau's estimate for July 1, 2025, 1,916 fewer than in 2020 (−2.0%). That works out to 89 people per square mile of land. No town dominates: Thibodaux, the largest, has 15,573 residents, 16.3% of the total. Together its 3 incorporated places hold 20.5% of those residents; the other 79.5% live outside any of them. Reported testing is thin here: 18 tests over 2019, or 0.2 for every 1,000 residents (2025 estimate), where Louisiana as a whole comes to 0.5.

From Thibodaux to Golden Meadow, CDC publishes no figure by town: each reads Lafourche Parish's.

The cities and towns in Lafourche Parish by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Thibodaux15,573−2.1%16.3%
Lockport2,333−6.2%2.4%
Golden Meadow1,636−6.5%1.7%

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).

Lafourche Parish, Homes

Homes in Lafourche Parish

Of Lafourche Parish's 41,164 homes, 72% are detached houses, against 65% across Louisiana; 16% are mobile homes. Half of its homes were built before 1981, close to Louisiana's 1982: 18% date from before 1960 and 26% from 2000 or later. Owners live in 78% of the occupied homes (Louisiana: 67%), so for most households a test and a fix are their own to order.

Homes in Lafourche Parish, Louisiana, 2019 to 2023
HomesLafourche ParishLouisiana
Housing units41,1642,094,002
Detached houses72%65%
In buildings of 5 or more5%11%
Mobile homes16%13%
Built before 196018%19%
Built since 200026%27%
Middle year built19811982
Owner-occupied78%67%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.