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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 18 counties in Louisiana
18 counties ranked by average water quality score
| Rank | County | Avg Score | Grade | Cities | Population | Score Range |
|---|---|---|---|---|---|---|
| 1 | Calcasieu County | 100 | A | 2 | 103,989 | 100 - 100 |
| 2 | Lafayette County | 100 | A | 1 | 169,389 | 100 - 100 |
| 3 | Rapides County | 100 | A | 1 | 66,798 | 100 - 100 |
| 4 | Iberia County | 100 | A | 1 | 59,928 | 100 - 100 |
| 5 | St. Bernard County | 100 | A | 1 | 44,783 | 100 - 100 |
| 6 | St. John the Baptist County | 100 | A | 1 | 31,965 | 100 - 100 |
| 7 | Lincoln County | 100 | A | 1 | 22,468 | 100 - 100 |
| 8 | Tangipahoa County | 100 | A | 1 | 21,135 | 100 - 100 |
| 9 | Lafourche County | 100 | A | 1 | 14,862 | 100 - 100 |
| 10 | Bossier County | 99 | A | 1 | 79,506 | 99 - 99 |
| 11 | Natchitoches County | 98 | A | 1 | 27,693 | 98 - 98 |
| 12 | East Baton Rouge County | 97 | A | 3 | 642,268 | 90 - 100 |
| 13 | Terrebonne County | 96 | A | 1 | 11,658 | 96 - 96 |
| 14 | St. Tammany County | 95 | A | 2 | 48,547 | 90 - 100 |
| 15 | St. Landry County | 60 | D | 1 | 20,388 | 60 - 60 |
| 16 | Orleans County | 58 | F | 1 | 334,903 | 58 - 58 |
| 17 | Ouachita County | 58 | F | 1 | 57,000 | 58 - 58 |
| 18 | Caddo County | 57 | F | 1 | 192,378 | 57 - 57 |
3 cities • 642,268 residents
1 cities • 334,903 residents
See all 18 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 18 counties and 22 cities analyzed, this data helps residents understand regional water quality patterns in Louisiana. County scores range from 57/100 to 100/100, reflecting the diversity of water sources and treatment infrastructure across the state.
Currently, 4 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.