Plaquemines Parish, LA
drinking water quality
22,289 residents · 5 public water systems · 8 ZIP codes
EPA sampled 2 of 5 public water systems here, together serving about 29,952 people. The highest reading was PFOS at 4.6 ng/L at Port Sulphur Water District. 1 of the sampled system was above a federal limit. Last sampled 8/6/2025.
What was found
| Compound | Highest result | Federal limit | Ratio |
|---|---|---|---|
| PFOS | 4.6 ng/L | 4 ng/L | 1.1× |
Also detected, with no federal limit set: lithium (11000 ng/L), PFBA (5.6 ng/L).
Health-based violations
Separately from PFAS, EPA records 29 health-based violations across 2 of the parish’s water systems since 2020, the most recent in 2026. They involved contaminant 2920, trihalomethanes, haloacetic acids.
What this means
PFAS are industrial chemicals that EPA describes as breaking down only very slowly in the environment. In April 2024 EPA set the first enforceable national limits: 4 ng/L for PFOA and PFOS, 10 ng/L for PFHxS, PFNA and GenX.
These figures are county-level and come from EPA’s sampling of public water systems. They describe the worst result found in the county, not what comes out of any particular tap — that depends on which system serves the address, and on the plumbing in the building. A private well is not covered by this programme at all.
ZIP codes in Plaquemines Parish
70037 · 70038 · 70040 · 70041 · 70050 · 70082 · 70083 · 70091
Readings are parish-level, so every ZIP here shares the figure above. Search your ZIP on the map to see it in context.