Public water system · MA3010000
ActiveArlington Water Dept. (MWRA)
At a glance
Arlington Water Dept. (MWRA) (PWSID MA3010000) is an active community water system in Middlesex County, Massachusetts. It reports serving 46,308 people through 12,765 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in January 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
46,308
Service connections
12,765
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Arlington Water Dept. (MWRA) compare with other water systems in Middlesex County?
By EPA's size categories, Arlington Water Dept. (MWRA) is a large system (10,001 to 100,000 people). Middlesex County has 204 active public water systems. Its population served is about 5.8 times the county average of 7,986 people per system, and accounts for 2.8% 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 Arlington Water Dept. (MWRA) is about 6.9 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 Arlington Water Dept. (MWRA)?
EPA lists Arlington 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 Arlington Water Dept. (MWRA) have drinking water violations?
EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in January 2020. The violations listed here began between January 1992 and January 2020. By type: 4 required treatment not met and 2 monitoring and reporting. The contaminant or rule involved most often is Lead and Copper Rule (4 of them). EPA lists 5 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 |
|---|---|---|---|---|
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Asbestoscode 1094 | No | Resolved |
| 2015-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 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 |
| 1992-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1992-01-01 | Required treatment not metFailure to Filter (SWTR) · code 42 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
All 6 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.
Arlington Water Dept. (MWRA): frequently asked questions
Who runs Arlington Water Dept. (MWRA)?
Arlington Water Dept. (MWRA) (PWSID MA3010000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Arlington Water Dept. (MWRA) serve?
Arlington Water Dept. (MWRA) reports serving 46,308 people through 12,765 service connections in Middlesex County, Massachusetts.
Where does Arlington 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 Arlington Water Dept. (MWRA) have any drinking water violations?
EPA's records list 6 violations for this system; 4 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 Arlington 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. EPA's records list 6 violations for this system; 4 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 Arlington Water Dept. (MWRA)'s water quality report?
As a community water system, Arlington 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 |
| Somerville Water Dept. (MWRA) | Middlesex | 81,045 | 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 |
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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, “Arlington Water Dept. (MWRA), PWSID MA3010000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/arlington-water-dept-mwra-ma3010000 (data as of October 1, 2026).