Water quality by parish
in Louisiana
EPA sampled public water systems across Louisiana for PFAS under its UCMR 5 programme. Of the 64 parishes, 6 have a reading above a federal limit and 3 have not been sampled at all — which is not a clean result, only an absence of one. Each parish below shows what was found, at what concentration, and at which utility.
| parish | Population | Worst result | Compound |
|---|---|---|---|
| Concordia Parish | 17,797 | 5.0× | PFOA · 20.1 ng/L |
| St. Martin Parish | 51,218 | 1.6× | PFOA · 6.4 ng/L |
| Iberville Parish | 29,766 | 1.6× | PFOA · 6.2 ng/L |
| Plaquemines Parish | 22,289 | 1.1× | PFOS · 4.6 ng/L |
| Ascension Parish | 133,534 | 1.1× | PFOS · 4.5 ng/L |
| Orleans Parish | 362,701 | 1.1× | PFOS · 4.5 ng/L |
| Vermilion Parish | 57,641 | under the limit | PFHxS · 3.7 ng/L |
| Richland Parish | 19,643 | under the limit | PFHxS · 3.4 ng/L |
| Acadia Parish | 56,604 | under the limit | — |
| Allen Parish | 22,501 | under the limit | — |
| Assumption Parish | 20,050 | under the limit | — |
| Avoyelles Parish | 38,373 | under the limit | — |
| Beauregard Parish | 36,695 | under the limit | — |
| Bienville Parish | 12,412 | under the limit | — |
| Bossier Parish | 131,102 | under the limit | — |
| Caddo Parish | 224,893 | under the limit | — |
| Calcasieu Parish | 206,861 | under the limit | — |
| Caldwell Parish | 9,393 | not sampled | — |
| Cameron Parish | 4,678 | under the limit | — |
| Catahoula Parish | 8,280 | not sampled | — |
| Claiborne Parish | 13,537 | under the limit | — |
| De Soto Parish | 27,274 | under the limit | — |
| East Baton Rouge Parish | 453,022 | under the limit | — |
| East Carroll Parish | 6,892 | under the limit | — |
| East Feliciana Parish | 19,112 | under the limit | — |
| Evangeline Parish | 31,745 | under the limit | — |
| Franklin Parish | 19,107 | under the limit | — |
| Grant Parish | 22,109 | under the limit | — |
| Iberia Parish | 67,540 | under the limit | — |
| Jackson Parish | 14,797 | under the limit | — |
| Jefferson Parish | 427,253 | under the limit | — |
| Jefferson Davis Parish | 31,436 | under the limit | — |
| Lafayette Parish | 254,241 | under the limit | — |
| Lafourche Parish | 95,342 | under the limit | — |
| LaSalle Parish | 14,702 | not sampled | — |
| Lincoln Parish | 48,243 | under the limit | — |
| Livingston Parish | 152,886 | under the limit | — |
| Madison Parish | 9,093 | under the limit | — |
| Morehouse Parish | 23,787 | under the limit | — |
| Natchitoches Parish | 35,982 | under the limit | — |
| Ouachita Parish | 157,874 | under the limit | — |
| Pointe Coupee Parish | 19,845 | under the limit | — |
| Rapides Parish | 125,899 | under the limit | — |
| Red River Parish | 7,238 | under the limit | — |
| Sabine Parish | 21,746 | under the limit | — |
| St. Bernard Parish | 44,783 | under the limit | — |
| St. Charles Parish | 50,400 | under the limit | — |
| St. Helena Parish | 10,857 | under the limit | — |
| St. James Parish | 19,110 | under the limit | — |
| St. John the Baptist Parish | 39,694 | under the limit | — |
| St. Landry Parish | 80,869 | under the limit | — |
| St. Mary Parish | 46,799 | under the limit | — |
| St. Tammany Parish | 277,615 | under the limit | — |
| Tangipahoa Parish | 139,823 | under the limit | — |
| Tensas Parish | 3,844 | under the limit | — |
| Terrebonne Parish | 103,864 | under the limit | — |
| Union Parish | 20,617 | under the limit | — |
| Vernon Parish | 45,819 | under the limit | — |
| Washington Parish | 45,090 | under the limit | — |
| Webster Parish | 35,184 | under the limit | — |
| West Baton Rouge Parish | 28,425 | under the limit | — |
| West Carroll Parish | 9,254 | under the limit | — |
| West Feliciana Parish | 15,155 | under the limit | — |
| Winn Parish | 13,405 | under the limit | — |