Public water system · MA3057000
ActiveChelsea Water Dept. (MWRA)
At a glance
Chelsea Water Dept. (MWRA) (PWSID MA3057000) is an active community water system in Suffolk County, Massachusetts. It reports serving 40,787 people through 5,100 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 11 are health-based, and the most recent began in July 2016.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
40,787
Service connections
5,100
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Chelsea Water Dept. (MWRA) compare with other water systems in Suffolk County?
By EPA's size categories, Chelsea Water Dept. (MWRA) is a large system (10,001 to 100,000 people). Suffolk County has 9 active public water systems, and Chelsea Water Dept. (MWRA) is the 4th-largest of them by population served. Its population served is well below the county average of 375,415 people per system, and accounts for 1.2% of the 3,378,736 people reported by systems filed under the county. Across Massachusetts, the 1,636 active systems average 6,275 people each. Nationally, the average active community water system reports serving 6,703 people, so Chelsea Water Dept. (MWRA) is about 6.1 times 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. Massachusetts has 531 active community water systems, 32% of the state's 1,636 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 126 Massachusetts systems (7.7%) list purchased surface water as their primary source.
Who owns and regulates Chelsea Water Dept. (MWRA)?
EPA lists Chelsea Water Dept. (MWRA) as owned by a local government. The MA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 4 of the 9 active systems in Suffolk County (44%) are also owned by a local government.
Does Chelsea Water Dept. (MWRA) have drinking water violations?
Of the 12 most recent violations in EPA's records, 11 are health-based, and the most recent began in July 2016. The violations listed here began between June 1995 and July 2016. By type: 7 contaminant level above the legal limit, 4 required treatment not met and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (7 of them). EPA lists 7 as archived and 5 as resolved. 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. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2016-07-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2010-01-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2007-01-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1999-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1997-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1996-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-06-01 | 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.
Chelsea Water Dept. (MWRA): frequently asked questions
Who runs Chelsea Water Dept. (MWRA)?
Chelsea Water Dept. (MWRA) (PWSID MA3057000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Chelsea Water Dept. (MWRA) serve?
Chelsea Water Dept. (MWRA) reports serving 40,787 people through 5,100 service connections in Suffolk County, Massachusetts.
Where does Chelsea Water Dept. (MWRA) get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Chelsea Water Dept. (MWRA) have any drinking water violations?
Of the 12 most recent violations in EPA's records, 11 are health-based, and the most recent began in July 2016. 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 Chelsea Water Dept. (MWRA)'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, 11 are health-based, and the most recent began in July 2016. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.
Where can I find Chelsea Water Dept. (MWRA)'s water quality report?
As a community water system, Chelsea Water Dept. (MWRA) 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 Suffolk County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| MWRA | Suffolk | 2,580,000 | Community | Surface water |
| Boston Water and Sewer Commission (MWRA) | Suffolk | 675,647 | Community | Purchased surface water |
| Revere Water Division (MWRA) | Suffolk | 62,186 | Community | Purchased surface water |
| Winthrop Water Division, (MWRA) | Suffolk | 19,316 | Community | Purchased surface water |
| Rocky Mt Sprg @ Supreme Liq Boston Vnd | Suffolk | 400 | Transient non-community | Purchased groundwater |
| Deer Island (MWRA) | Suffolk | 350 | Non-transient non-community | Purchased surface water |
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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, “Chelsea Water Dept. (MWRA), PWSID MA3057000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/chelsea-water-dept-mwra-ma3057000 (data as of October 1, 2026).