Public water system · MA3274000
ActiveSomerville Water Dept. (MWRA)
At a glance
Somerville Water Dept. (MWRA) (PWSID MA3274000) is an active community water system in Middlesex County, Massachusetts. It reports serving 81,045 people through 14,919 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, 10 are health-based, and the most recent began in January 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
81,045
Service connections
14,919
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Somerville Water Dept. (MWRA) compare with other water systems in Middlesex County?
By EPA's size categories, Somerville Water Dept. (MWRA) is a large system (10,001 to 100,000 people). Middlesex County has 204 active public water systems, and Somerville Water Dept. (MWRA) is the 4th-largest of them by population served. Its population served is about 10 times the county average of 7,986 people per system, and accounts for 5% of the 1,629,099 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 Somerville Water Dept. (MWRA) is about 12 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 Somerville Water Dept. (MWRA)?
EPA lists Somerville 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. 66 of the 204 active systems in Middlesex County (32%) are also owned by a local government.
Does Somerville Water Dept. (MWRA) have drinking water violations?
Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2020. The violations listed here began between January 1993 and January 2020. By type: 6 required treatment not met, 4 contaminant level above the legal limit and 2 monitoring and reporting. The contaminant or rule involved most often is Lead and Copper Rule (7 of them). EPA lists 8 as resolved, 2 as addressed and 2 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. Addressed means the violation is not resolved or archived and is covered by formal enforcement. 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 |
|---|---|---|---|---|
| 2020-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Addressed |
| 2019-11-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Addressed |
| 2010-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2008-01-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2000-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2000-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2000-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1998-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1995-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Asbestoscode 1094 | No | Archived |
| 1994-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1993-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
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.
Somerville Water Dept. (MWRA): frequently asked questions
Who runs Somerville Water Dept. (MWRA)?
Somerville Water Dept. (MWRA) (PWSID MA3274000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Somerville Water Dept. (MWRA) serve?
Somerville Water Dept. (MWRA) reports serving 81,045 people through 14,919 service connections in Middlesex County, Massachusetts.
Where does Somerville 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 Somerville Water Dept. (MWRA) have any drinking water violations?
Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2020. 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 Somerville 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, 10 are health-based, and the most recent began in January 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.
Where can I find Somerville Water Dept. (MWRA)'s water quality report?
As a community water system, Somerville 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 Middlesex County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Lowell Regional Water Utility | Middlesex | 120,418 | Community | Surface water |
| Cambridge Water Department | Middlesex | 118,214 | Community | Surface water |
| Newton Water Dept. (MWRA) | Middlesex | 88,931 | Community | Purchased surface water |
| Framingham Water Dept. (MWRA) | Middlesex | 72,362 | Community | Purchased surface water |
| Malden Water Division (MWRA) | Middlesex | 66,263 | Community | Purchased surface water |
| Waltham Water Department | Middlesex | 65,218 | 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, “Somerville Water Dept. (MWRA), PWSID MA3274000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/somerville-water-dept-mwra-ma3274000 (data as of October 1, 2026).