Public water system · LA1101011
ActiveWater & Sewer Commission 4 of St Mary
At a glance
Water & Sewer Commission 4 of St Mary (PWSID LA1101011) is an active community water system in St. Mary Parish County, Louisiana. It reports serving 9,709 people through 3,011 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2025.
This page covers its drinking water system only; sewer and wastewater service are not part of EPA's drinking water records.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
9,709
Service connections
3,011
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Water & Sewer Commission 4 of St Mary compare with other water systems in St. Mary Parish County?
By EPA's size categories, Water & Sewer Commission 4 of St Mary is a medium system (3,301 to 10,000 people). St. Mary Parish County has 16 active public water systems, and Water & Sewer Commission 4 of St Mary is the 2nd-largest of them by population served. Its population served is about 146% above the county average of 3,945 people per system, and accounts for 15% of the 63,113 people reported by systems filed under the county. Across Louisiana, the 1,121 active systems average 4,685 people each. Nationally, the average active community water system reports serving 6,703 people, so Water & Sewer Commission 4 of St Mary is about 45% above that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Louisiana has 815 active community water systems, 73% of the state's 1,121 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 53 Louisiana systems (4.7%) list surface water as their primary source.
Who owns and regulates Water & Sewer Commission 4 of St Mary?
EPA lists Water & Sewer Commission 4 of St Mary as owned by a local government. The LA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 12 of the 16 active systems in St. Mary Parish County (75%) are also owned by a local government.
Does Water & Sewer Commission 4 of St Mary have drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2025. The violations listed here began between September 1994 and January 2025. By type: 12 contaminant level above the legal limit. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (6 of them). EPA lists 11 as resolved and 1 as archived. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2024-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2023-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2008-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2008-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2008-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2007-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2007-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2004-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1994-09-15 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Water & Sewer Commission 4 of St Mary: frequently asked questions
Who runs Water & Sewer Commission 4 of St Mary?
Water & Sewer Commission 4 of St Mary (PWSID LA1101011) is a community water system owned by a local government. It is regulated by the LA state drinking water program.
How many people does Water & Sewer Commission 4 of St Mary serve?
Water & Sewer Commission 4 of St Mary reports serving 9,709 people through 3,011 service connections in St. Mary Parish County, Louisiana.
Where does Water & Sewer Commission 4 of St Mary get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Water & Sewer Commission 4 of St Mary have any drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Water & Sewer Commission 4 of St Mary's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the LA state drinking water program.
Where can I find Water & Sewer Commission 4 of St Mary's water quality report?
As a community water system, Water & Sewer Commission 4 of St Mary must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in St. Mary Parish County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Morgan City Water System | St. Mary Parish | 12,703 | Community | Surface water |
| City of Patterson Water System | St. Mary Parish | 8,456 | Community | Surface water |
| City of Franklin Water Supply | St. Mary Parish | 8,325 | Community | Surface water |
| St Mary Water & Sewer Comm #3 | St. Mary Parish | 7,828 | Community | Surface water |
| St Mary Parish W&S #2 Bayou Vista | St. Mary Parish | 5,379 | Community | Purchased surface water |
| City of Berwick | St. Mary Parish | 5,024 | Community | Purchased surface water |
Related pages
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Water & Sewer Commission 4 of St Mary, PWSID LA1101011, Louisiana”, https://aquacensus.com/water-systems/louisiana/water-sewer-commission-4-of-st-mary-la1101011 (data as of October 1, 2026).