Total trihalomethanes (TTHM) above the legal limit in the period starting January 2026.
Serves about 8,456 people (2,591 connections) with surface water from its own intake, and buys water from St Mary Water & Sewer Comm #3 and St Mary Parish W&S #2 Bayou Vista.
From EPA's record for LA1101006. PurityMap is independent of City of Patterson Water System.
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6 health-based violations in the last 10 years, from EPA's SDWIS compliance database.
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| Jan–Mar 2026 | Total trihalomethanes (TTHM) | 0.09 mg/L | 0.080 mg/L | Archived |
| Oct–Dec 2025 | Total trihalomethanes (TTHM) | 0.091 mg/L | 0.080 mg/L | Archived |
| Jul–Sep 2025 | Total trihalomethanes (TTHM) | 0.083 mg/L | 0.080 mg/L | Archived |
| Apr–Jun 2025 | Total trihalomethanes (TTHM) | 0.082 mg/L | 0.080 mg/L | Archived |
| Jan–Mar 2025 | Total trihalomethanes (TTHM) | 0.082 mg/L | 0.080 mg/L | Archived |
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| Oct–Dec 2024 | Total trihalomethanes (TTHM) | 0.081 mg/L | 0.080 mg/L | Archived |
EPA required this system to test for 30 unregulated and emerging contaminants, from January 2024 to October 2024.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Perfluorobutanoic acid (PFBA) | 6.1 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoropentanoic acid (PFPeA) | 3.2 ng/L | No federal or state limit; shown for transparency | Detected, no limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 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 | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 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 | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 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 | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 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 | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 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 | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Lithium | < 9 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| 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 | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-01-08 to 2024-10-14 | UCMR5 Analytical Results: CITY OF PATTERSON WATER SYSTEM (LA1101006) |
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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.
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Follow this water →City of Patterson Water System's phone number on EPA record is 985-395-5205. Its mailing address is City Hall (Patterson Water System), P.O. Box 367, PATTERSON, LA 70392.
According to EPA's record, City of Patterson Water System uses surface water from its own intake, and buys water from St Mary Water & Sewer Comm #3 and St Mary Parish W&S #2 Bayou Vista.
EPA's record shows 6 health-based violations for City of Patterson Water System in the 10 years to July 9, 2026. Total trihalomethanes (TTHM) were above the legal limit in the period starting January 2026. EPA also lists 1 missed or late test or report in 10 years. The record comes from EPA's SDWIS compliance database.
Lead was not detected at the 90th percentile of tap samples in City of Patterson Water System's latest lead and copper round, which ended in December 2023. The federal action level is 15 µg/L.
PurityMap has no verified website for City of Patterson Water System. Its phone number on EPA record is 985-395-5205. Its mailing address on EPA record is City Hall (Patterson Water System), P.O. Box 367, PATTERSON, LA 70392. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.