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Manganese in Louisiana well water, by county

By the Tested Water teamLab data from the USGS and EPA Water Quality Portal, 2000 to 2021Updated November 8, 2026

Manganese is widespread, over the limit in 15% or more of tested wells, in 12 of the 24 Louisiana counties with 10 or more tested wells. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.

Find a manganese test See every county

How Louisiana compares with the rest of the country

Across Louisiana, about 2 in 10 tested wells had manganese over the EPA health advisory of 0.3 mg/L (121 of 566). Across all tested wells in the US it's about 1 in 7. So manganese turns up somewhat more often in Louisiana than in the country as a whole. Check your county below.

Why it matters: High levels over many years may affect the nervous system, and babies are more sensitive to it. It also leaves black stains.

Manganese dissolves out of rock and soil, especially in water with little oxygen.

Manganese in tested wells, county by county

Share of each county's tested wells with at least one result over the EPA health advisory of 0.3 mg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.

CountyWells testedWells over the limitLevel
Franklin Parish 28
50% 14 of 28
 Widespread
Natchitoches Parish 26
50% 13 of 26
 Widespread
Jefferson Davis Parish 14
50% 7 of 14
 Widespread
Lafayette Parish 38
47% 18 of 38
 Widespread
Vermilion Parish 15
40% 6 of 15
 Widespread
Calcasieu Parish 14
36% 5 of 14
 Widespread
Red River Parish 20
35% 7 of 20
 Widespread
Allen Parish 12
33% 4 of 12
 Widespread
Morehouse Parish 10
30% 3 of 10
 Widespread
Bossier Parish 39
28% 11 of 39
 Widespread
Evangeline Parish 11
27% 3 of 11
 Widespread
Caddo Parish 53
15% 8 of 53
 Widespread
Tangipahoa Parish 15
13% 2 of 15
 Worth checking
Ouachita Parish 10
10% 1 of 10
 Worth checking
De Soto Parish 31
3% 1 of 31
 Rare
St. Tammany Parish 18
0% 0 of 18
 Rare
Acadia Parish 17
0% 0 of 17
 Rare
East Baton Rouge Parish 17
0% 0 of 17
 Rare
Rapides Parish 14
0% 0 of 14
 Rare
Vernon Parish 14
0% 0 of 14
 Rare
Webster Parish 12
0% 0 of 12
 Rare
East Feliciana Parish 11
0% 0 of 11
 Rare
Beauregard Parish 10
0% 0 of 10
 Rare
Bienville Parish 10
0% 0 of 10
 Rare

27 more Louisiana counties have 1 to 9 tested wells for manganese, too few to rate.

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Where to get your well tested for manganese in Louisiana

1

Your county health department

Louisiana doesn't run a statewide free testing program that we know of. Some county health departments test wells or sell kits, so call yours first.

Louisiana's private well page
3

A mail-in kit

Fill the bottles at your kitchen tap and mail them back. We mark the kits that include manganese.

Compare kits

Keep reading about wells in Louisiana

Questions people ask about manganese in Louisiana

Is there manganese in Louisiana well water?

Manganese is widespread, over the limit in 15% or more of tested wells, in 12 of the 24 Louisiana counties with 10 or more tested wells. Across Louisiana, about 2 in 10 tested wells had manganese over the EPA health advisory of 0.3 mg/L (121 of 566). Across all tested wells in the US it's about 1 in 7. So manganese turns up somewhat more often in Louisiana than in the country as a whole. Check your county below.

Where can I get my well tested for manganese in Louisiana?

Use a lab certified by Louisiana for drinking water, or a mail-in kit that includes manganese from a certified lab. Some county health departments test wells too, so call yours first.

compare mail-in kits.

Where these numbers come from

  • Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA health advisory of 0.3 mg/L. Wells tested for studies and monitoring, not a random sample of homes.
  • Likely overstated: our own check of who tested the wells, when and where. How we check.
  • State programs and links: Louisiana Department of Health.