Quick answer
About 461,000 people in Louisiana (10.2% of residents) got their water from private wells in 2010, according to USGS estimates. Louisiana Department of Health runs the state’s private well guidance. We didn’t find a free statewide well testing program in Louisiana. Certified labs charge for each test, and some county health departments offer lower-cost bacteria and nitrate tests.
- People on private wells
- 461,089
- Share of residents
- 10.2%
- Rank among states
- 29th
- Well users modeled above 10 µg/L arsenic
- 1.8%
Where to get your well tested in Louisiana
- Louisiana Department of Health: Private Well Testing Information, the state’s guidance for private well owners.
Free or low-cost testing
We didn’t find a free statewide program in Louisiana. Certified labs charge per test; county health departments sometimes offer lower-cost bacteria and nitrate tests.
Mail-in lab kits are another option when no local lab is convenient. See well water test kits for what home kits can and can’t tell you.
What to test for
- Every year: total coliform bacteria and nitrate.
- Before buying equipment: pH, hardness, iron, manganese and, if there’s a smell, hydrogen sulfide.
- Based on location: arsenic, uranium and radon, PFAS, and lead in older plumbing.
Private wells by county
Estimated people relying on private wells in each Louisiana county in 2010, the share of residents that represents, and the modeled share of well users with arsenic above 10 µg/L. These are USGS model estimates (2010 population), not measurements of any well. Arsenic is hidden for counties with fewer than 500 well users.
| County | People on wells | Share | Arsenic >10 µg/L |
|---|---|---|---|
| St. Tammany Parish | 49,873 | 21.3% | 1.4% |
| Tangipahoa Parish | 37,934 | 31.3% | 1.5% |
| Vermilion Parish | 27,130 | 46.8% | 2.6% |
| Calcasieu Parish | 26,156 | 13.6% | 1.1% |
| Lafayette Parish | 23,187 | 10.5% | 2.1% |
| Caddo Parish | 21,815 | 8.6% | 2.0% |
| Livingston Parish | 21,699 | 16.9% | 1.5% |
| Washington Parish | 21,322 | 45.2% | 2.3% |
| Ascension Parish | 19,694 | 18.4% | 1.8% |
| Vernon Parish | 18,459 | 35.3% | 1.0% |
| Acadia Parish | 18,352 | 29.7% | 2.8% |
| Bossier Parish | 16,084 | 13.7% | 2.0% |
Show all 64 counties
| Iberia Parish | 11,235 | 15.3% | 1.9% |
| Sabine Parish | 10,430 | 43.0% | 1.2% |
| Beauregard Parish | 9,419 | 26.4% | 1.0% |
| De Soto Parish | 8,730 | 32.7% | 1.8% |
| St. Landry Parish | 8,546 | 10.2% | 2.2% |
| Franklin Parish | 8,171 | 39.3% | 2.1% |
| Rapides Parish | 7,367 | 5.6% | 1.9% |
| Ouachita Parish | 6,698 | 4.4% | 1.5% |
| St. Helena Parish | 6,617 | 59.1% | 2.0% |
| St. Martin Parish | 6,546 | 12.5% | 1.4% |
| Richland Parish | 6,105 | 29.5% | 2.1% |
| Jefferson Davis Parish | 5,451 | 17.3% | 1.1% |
| Natchitoches Parish | 5,231 | 13.2% | 1.0% |
| Webster Parish | 4,796 | 11.6% | 1.4% |
| Evangeline Parish | 4,090 | 12.0% | 1.4% |
| Bienville Parish | 3,692 | 25.7% | 1.0% |
| Allen Parish | 3,468 | 13.5% | 1.0% |
| Claiborne Parish | 3,132 | 18.2% | 1.0% |
| Grant Parish | 3,107 | 13.9% | 2.9% |
| East Feliciana Parish | 2,858 | 14.1% | 3.2% |
| Red River Parish | 2,674 | 29.4% | 1.0% |
| Pointe Coupee Parish | 2,551 | 11.2% | 4.7% |
| East Baton Rouge Parish | 2,466 | 0.6% | 2.0% |
| Morehouse Parish | 2,421 | 8.7% | 1.7% |
| Union Parish | 2,299 | 10.1% | 1.4% |
| Winn Parish | 2,286 | 14.9% | 2.0% |
| Lincoln Parish | 2,146 | 4.6% | 1.0% |
| Iberville Parish | 2,043 | 6.1% | 1.9% |
| Avoyelles Parish | 1,988 | 4.7% | 1.9% |
| Jackson Parish | 1,909 | 11.7% | 1.3% |
| Orleans Parish | 1,306 | 0.4% | 1.7% |
| Cameron Parish | 1,137 | 16.6% | 2.0% |
| Catahoula Parish | 1,090 | 10.5% | 2.0% |
| St. Mary Parish | 894 | 1.6% | 2.0% |
| West Carroll Parish | 862 | 7.4% | 2.4% |
| Concordia Parish | 821 | 3.9% | 1.4% |
| LaSalle Parish | 671 | 4.5% | 2.7% |
| Caldwell Parish | 596 | 5.9% | 2.4% |
| West Feliciana Parish | 590 | 3.8% | 4.0% |
| St. John the Baptist Parish | 495 | 1.1% | – |
| West Baton Rouge Parish | 437 | 1.8% | – |
| St. Charles Parish | 346 | 0.7% | – |
| Jefferson Parish | 317 | 0.1% | – |
| Madison Parish | 293 | 2.4% | – |
| Assumption Parish | 256 | 1.1% | – |
| Tensas Parish | 233 | 4.4% | – |
| East Carroll Parish | 172 | 2.2% | – |
| Terrebonne Parish | 139 | 0.1% | – |
| St. James Parish | 112 | 0.5% | – |
| Plaquemines Parish | 101 | 0.4% | – |
| St. Bernard Parish | 31 | 0.1% | – |
| Lafourche Parish | 13 | 0.0% | – |
After you get results
Enter your numbers in the test results tool to see what needs treating and in what order. The guide to reading a well water test explains units and limits.
Common questions
Does Louisiana offer free well water testing?
We didn’t find a free statewide well testing program in Louisiana. Certified labs charge for each test, and some county health departments offer lower-cost bacteria and nitrate tests.
Who oversees private wells in Louisiana?
Louisiana Department of Health (Private Well Testing Information) publishes guidance for private well owners. Private wells aren’t covered by the federal Safe Drinking Water Act, so testing and treatment are up to the owner.
How many people use private wells in Louisiana?
USGS estimates about 461,000 people, or 10.2% of the population in 2010. That ranks 29th of the states covered by the estimate.
What should I test my well for in Louisiana?
Test every year for total coliform bacteria and nitrate, plus pH, hardness, iron and manganese before buying equipment. Ask the state program or a certified lab about local concerns such as arsenic, uranium or PFAS.