Radon in Louisiana: radon map by county

EPA's Map of Radon Zones puts 0 of Louisiana's 64 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 0 in Zone 2 and 64 in Zone 3. Of 203 building tests that radon laboratories reported for 2008 to 2017, 2.9% were at or above EPA's 4 pCi/L action level, against 36.5% nationally. The highest county share is Jefferson Parish (2.5% of 22 tests).

counties in Zone 1 (above 4 pCi/L predicted)

counties in Zone 2 (2 to 4)

counties in Zone 3 (below 2)

2.9%

of 203 lab tests at or above 4 pCi/L

Radon by county in Louisiana

EPA radon zone and radon test results for each county in Louisiana
County	EPA zone	Lab tests	Median	4+ pCi/L
Acadia Parish	Zone 3	1	0.7	0%
Allen Parish	Zone 3	n/a	n/a	n/a
Ascension Parish	Zone 3	11	0.5	0%
Assumption Parish	Zone 3	n/a	n/a	n/a
Avoyelles Parish	Zone 3	n/a	n/a	n/a
Beauregard Parish	Zone 3	n/a	n/a	n/a
Bienville Parish	Zone 3	n/a	n/a	n/a
Bossier Parish	Zone 3	10	0.2	5.6%
Caddo Parish	Zone 3	9	1.2	17.4%
Calcasieu Parish	Zone 3	35	0.1	0%
Caldwell Parish	Zone 3	n/a	n/a	n/a
Cameron Parish	Zone 3	1	0.1	0%
Catahoula Parish	Zone 3	n/a	n/a	n/a
Claiborne Parish	Zone 3	n/a	n/a	n/a
Concordia Parish	Zone 3	n/a	n/a	n/a
De Soto Parish	Zone 3	4	0.2	0%
East Baton Rouge Parish	Zone 3	16	0.7	0%
East Carroll Parish	Zone 3	n/a	n/a	n/a
East Feliciana Parish	Zone 3	n/a	n/a	n/a
Evangeline Parish	Zone 3	2	0.7	0%
Franklin Parish	Zone 3	1	5.7	100%
Grant Parish	Zone 3	n/a	n/a	n/a
Iberia Parish	Zone 3	1	2.4	0%
Iberville Parish	Zone 3	1	0.6	0%
Jackson Parish	Zone 3	n/a	n/a	n/a
Jefferson Davis Parish	Zone 3	n/a	n/a	n/a
Jefferson Parish	Zone 3	22	0.2	2.5%
Lafayette Parish	Zone 3	12	0.8	7.4%
Lafourche Parish	Zone 3	1	0.5	0%
LaSalle Parish	Zone 3	n/a	n/a	n/a
Lincoln Parish	Zone 3	3	1.5	0%
Livingston Parish	Zone 3	4	0.9	16.7%
Madison Parish	Zone 3	n/a	n/a	n/a
Morehouse Parish	Zone 3	n/a	n/a	n/a
Natchitoches Parish	Zone 3	2	0.5	0%
Orleans Parish	Zone 3	21	0.2	0%
Ouachita Parish	Zone 3	4	1.9	0%
Plaquemines Parish	Zone 3	2	0.5	0%
Pointe Coupee Parish	Zone 3	n/a	n/a	n/a
Rapides Parish	Zone 3	3	0.8	0%
Red River Parish	Zone 3	1	0.2	0%
Richland Parish	Zone 3	1	0.9	0%
Sabine Parish	Zone 3	1	0.1	0%
St. Bernard Parish	Zone 3	n/a	n/a	n/a
St. Charles Parish	Zone 3	1	0.9	0%
St. Helena Parish	Zone 3	n/a	n/a	n/a
St. James Parish	Zone 3	n/a	n/a	n/a
St. John the Baptist Parish	Zone 3	1	0.2	0%
St. Landry Parish	Zone 3	2	0.8	33.3%
St. Martin Parish	Zone 3	1	3.8	0%
St. Mary Parish	Zone 3	n/a	n/a	n/a
St. Tammany Parish	Zone 3	10	0.2	0%
Tangipahoa Parish	Zone 3	10	0.1	0%
Tensas Parish	Zone 3	n/a	n/a	n/a
Terrebonne Parish	Zone 3	5	0.5	0%
Union Parish	Zone 3	1	2.8	0%
Vermilion Parish	Zone 3	n/a	n/a	n/a
Vernon Parish	Zone 3	n/a	n/a	n/a
Washington Parish	Zone 3	1	0.1	0%
Webster Parish	Zone 3	1	0.6	0%
West Baton Rouge Parish	Zone 3	n/a	n/a	n/a
West Carroll Parish	Zone 3	n/a	n/a	n/a
West Feliciana Parish	Zone 3	n/a	n/a	n/a
Winn Parish	Zone 3	1	1.1	0%

Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).

What the zones mean

Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.

Radon in Louisiana: questions

What radon zone is Louisiana?

EPA's 1993 map does not give states one zone; it zones each county. In Louisiana, 0 counties are Zone 1, 0 Zone 2 and 64 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".

Which Louisiana counties have the highest radon levels?

By the share of laboratory tests at or above 4 pCi/L for 2008 to 2017 (counties with 20 or more tests): Jefferson Parish 2.5% (median 0.2 pCi/L, 22 tests); Calcasieu Parish 0% (median 0.1 pCi/L, 35 tests); Orleans Parish 0% (median 0.2 pCi/L, 21 tests).

How common is high radon in Louisiana?

2.9% of the 203 tests in the laboratory data for Louisiana (2008 to 2017) were at or above 4 pCi/L; the national share was 36.5%. Buildings are tested by choice, often because of a sale or a concern, so the share describes the tests on file, not every home.

Does Louisiana publish its own radon test data?

Louisiana's radon program reports county test results; the latest year with county results is 2022, shown on each county page.

Should I test for radon in Louisiana?

Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.

States bordering Louisiana

Radon in Arkansas (0 of 75 in Zone 1)Radon in Mississippi (0 of 82 in Zone 1)Radon in Texas (0 of 254 in Zone 1)

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Superfund sites in Louisiana · Radon map of every state

Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.