St. Tammany Parish County tap water
0 of 19 water systems serving St. Tammany Parish County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 94 community water systems list this county as served; 18 serve 3,300+ people with full PFAS testing.
- 24 had a health-based violation since 2021-10-26.
Largest systems serving this county
| System | Source | People served (whole system) | PFAS above a 2024 level? | Violations since 2021-10-26 |
|---|---|---|---|---|
| City of Slidell Water Supply | Groundwater | 35,547 | No | 1 |
| St Tam Parish- Bedico -Faubourg-Coquille | Groundwater | 18,372 | No | 0 |
| St Tam Parish - Briarwood Terrace | Groundwater | 17,536 | No | 0 |
| City of Covington Water Supply | Groundwater | 16,185 | No | 1 |
| City of Mandeville Water Supply | Groundwater | 13,000 | No | 0 |
| Utilities Inc - North Park Water Supply | Groundwater | 11,298 | No | 0 |
| Bayou Liberty Water Association | Groundwater | 10,791 | No | 0 |
| Magnolia-Eden Isles | Groundwater | 10,155 | No | 0 |
| St Tam Parish - Cross Gates Sd | Groundwater | 8,037 | No | 0 |
| Magnolia-Greenleaves | Groundwater | 8,031 | No | 0 |
| Lee Road Water Corporation | Groundwater | 7,665 | No | 0 |
| Magnolia-Resolve Whisperwood | Groundwater | 6,867 | No | 0 |
Which one is yours? A county usually has several utilities. Your bill or your utility's annual water-quality report names yours. Population is for the whole system, which can cross county lines.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.