No open health-based violations on EPA record in the last 10 years.
Serves about 10,484 people (3,494 connections) with surface water from its own intake, and buys water from St John Water District 3.
From EPA's record for LA1095003. PurityMap is independent of St John Water District 1.
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1 health-based violation in the last 10 years, from EPA's SDWIS compliance database.
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| From June 2019 | Interim Enhanced Surface Water Treatment Rule | – | – | Resolved |
EPA required this system to test for 30 unregulated and emerging contaminants, from March 2025 to September 2025.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Lithium | 10.3 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit | Above the referenced health-based guidance value | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorobutanoic acid (PFBA) | 6 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-03-25 to 2025-09-23 | UCMR5 Analytical Results: ST JOHN WATER DISTRICT 1 (LA1095003) |
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
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Screening: quick check, not lab-grade
Safe Home (EnviroTestKits)
Lead, read as one of three ranges: 0–4, 5–15 or 15+ ppb
Turnaround: 5 minutes
What it can't tell you: It shows a lead range, not an exact level, and tests nothing else unless you pay extra for the optional lab test.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638 · 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Get PurityMap updates about this water system.
Follow this water →St John Water District 1's phone number on EPA record is 985-652-9569. Its mailing address is 1811 WEST AIRLINE HWY., LAPLACE, LA 70068.
According to EPA's record, St John Water District 1 uses surface water from its own intake, and buys water from St John Water District 3.
EPA's record shows 1 health-based violation for St John Water District 1 in the 10 years to July 9, 2026. No open health-based violations on EPA record in the last 10 years. EPA also lists 2 missed or late tests or reports in 10 years. The record comes from EPA's SDWIS compliance database.
The 90th-percentile lead result in St John Water District 1's latest lead and copper round, which ended in December 2024, was 2 µg/L, below the federal action level of 15 µg/L.
PurityMap has no verified website for St John Water District 1. Its phone number on EPA record is 985-652-9569. Its mailing address on EPA record is 1811 WEST AIRLINE HWY., LAPLACE, LA 70068. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.