City of Patterson Water System water quality report, rewritten
- Serves
- 8,456
- Connections
- 2,591
- Water source
- Surface water
- Based in
- Patterson, LA
- County
- St. Mary Parish
- Owner
- Local government
The ZIP code it serves
PWSID LA1101006 · EPA data
Read this first
Nothing in the federal data for this utility is above a health goal. That covers PFAS, lithium, lead and copper; it does not cover everything, so read what this report cannot tell you below.
6 health-based violations since 2016. Details are below.
What was found
Highlighted: above the health goal, or EPA’s health benchmark where there is no goal. Circled: above the legal limit in at least one sample, or the action level. Every scale puts that line at its middle.
Also found, with no federal limit
EPA measured these PFAS to learn how often they occur. None has a legal limit or a health goal yet.
| Compound | Highest sample | Found in | Certification claim |
|---|---|---|---|
| PFBA | 6.1 ppt | 2 of 4 | None covers it |
| PFPeA | 3.2 ppt | 1 of 4 | None covers it |
Tested and not found
Below EPA’s minimum reporting level in every sample taken from Jan. 8, 2024 to Oct. 14, 2024. Not found means not measured above that level, which is not the same as zero.
All 29 compounds tested and not found
- 11Cl-PF3OUdS
- 4:2 FTS
- 6:2 FTS
- 8:2 FTS
- 9Cl-PF3ONS
- ADONA
- HFPO-DA (GenX)
- Lead
- Lithium
- NEtFOSAA
- NFDHA
- NMeFOSAA
- PFBS
- PFDA
- PFDoA
- PFEESA
- PFHpA
- PFHpS
- PFHxA
- PFHxS
- PFMBA
- PFMPA
- PFNA
- PFOA
- PFOS
- PFPeS
- PFTA
- PFTrDA
- PFUnA
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2026 to March 31, 2026 | 0.09 MG/L | Archived |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Oct. 1, 2025 to Dec. 31, 2025 | 0.091 MG/L | Archived |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2025 to Sept. 30, 2025 | 0.083 MG/L | Archived |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | April 1, 2025 to June 30, 2025 | 0.082 MG/L | Archived |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2025 to March 31, 2025 | 0.082 MG/L | Archived |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Oct. 1, 2024 to Dec. 31, 2024 | 0.081 MG/L | Archived |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown. | ||||
What this report cannot tell you
- Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in City of Patterson Water System’s own annual report, which it must send you every year.
- Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
- Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from Jan. 8, 2024 to Oct. 14, 2024.
Other Louisiana utilities
- Baton Rouge Water Company596,844
- New Orleans Carrollton Water Works334,903
- E Jefferson Ww District 1275,163
- City of Shreveport Water System192,378
- Lafayette Utilities Water System169,389
- W Jefferson Ww District 2140,264
- Schriever Water Treatment Service Area116,460
- Lafourche Water District 181,609
- City of Bossier City Water System79,506
- City of Lake Charles Water System79,500
- Ward II Water District78,147
- Tangipahoa Parish Water District75,873
Sources
- EPA UCMR 5 occurrence data, file of Aug. 27, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q2
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
What to do next
Nothing here is above a health goal
In the federal data for this utility. That data does not cover everything, which is why the next step matters.
Every contaminant TapBuff tracksGet the utility’s own report
City of Patterson Water System must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.
How to read itTest your own tap for lead
Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.
Lead in your water: what to doDecide if you want a filter at all
A filter for taste or chlorine is a preference, not a need. The standards say what each kind can do.
NSF/ANSI standards, decoded