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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Compare water quality across 20 counties in Louisiana
20 counties ranked by average water quality score
| Rank | County | Avg Score | Grade | Cities | Population | Score Range |
|---|---|---|---|---|---|---|
| 1 | Tangipahoa County | 96 | A+ | 1 | 21,359 | 96 - 96 |
| 2 | Lafayette County | 93 | A | 1 | 121,374 | 93 - 93 |
| 3 | Ouachita County | 93 | A | 1 | 47,702 | 93 - 93 |
| 4 | Caddo County | 93 | A | 1 | 187,593 | 93 - 93 |
| 5 | Ascension County | 89 | A- | 1 | 33,197 | 89 - 89 |
| 6 | St. Tammany County | 84 | B+ | 2 | 41,973 | 81 - 87 |
| 7 | Iberia County | 84 | B+ | 1 | 28,555 | 84 - 84 |
| 8 | Lincoln County | 83 | B+ | 1 | 24,447 | 83 - 83 |
| 9 | Orleans County | 82 | B+ | 1 | 383,997 | 82 - 82 |
| 10 | Jefferson County | 81 | B+ | 5 | 162,390 | 67 - 95 |
| 11 | Bossier County | 81 | B+ | 1 | 62,701 | 81 - 81 |
| 12 | St. Landry County | 81 | B+ | 1 | 15,786 | 81 - 81 |
| 13 | East Baton Rouge County | 75 | B | 5 | 309,967 | 56 - 86 |
| 14 | St. Bernard County | 72 | B- | 1 | 21,562 | 72 - 72 |
| 15 | St. John the Baptist County | 71 | B- | 1 | 28,841 | 71 - 71 |
| 16 | Natchitoches County | 68 | C+ | 1 | 17,783 | 68 - 68 |
| 17 | Calcasieu County | 61 | C | 2 | 104,801 | 56 - 65 |
| 18 | Lafourche County | 59 | C- | 1 | 15,948 | 59 - 59 |
| 19 | Rapides County | 54 | D | 1 | 45,275 | 54 - 54 |
| 20 | Terrebonne County | 52 | D | 1 | 33,727 | 52 - 52 |
1 cities • 21,359 residents
1 cities • 121,374 residents
1 cities • 47,702 residents
1 cities • 187,593 residents
1 cities • 33,197 residents
2 cities • 41,973 residents
1 cities • 28,555 residents
1 cities • 24,447 residents
1 cities • 383,997 residents
5 cities • 162,390 residents
1 cities • 62,701 residents
1 cities • 15,786 residents
See all 20 counties in the ranking table above
Our county-level water quality analysis aggregates data from municipal water systems across Louisiana. Each county's score represents the average water quality across all analyzed cities within that county, weighted by population served.
With 20 counties and 30 cities analyzed, this data helps residents understand regional water quality patterns in Louisiana. County scores range from 52/100 to 96/100, reflecting the diversity of water sources and treatment infrastructure across the state.
Currently, 5 counties in Louisiana have average scores below 70, indicating potential water quality concerns. Residents in these areas should review their city's specific report and consider water filtration options.