Public water system · MA4065000

Active

Cohasset Water Dept

At a glance

Cohasset Water Dept (PWSID MA4065000) is an active community water system in Norfolk County, Massachusetts. It reports serving 7,555 people through 2,692 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, none is health-based, and the most recent began in July 2022.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

7,555

Service connections

2,692

Primary source

Surface water

System type

CWS

Community water system

System record

PWSIDMA4065000

System typeCommunity water system

Activity statusActive

Population served7,555

Service connections2,692

Primary water sourceSurface water

Owner typeLocal government

Primacy agencyMA state drinking water program

City servedCohasset

StateMassachusetts

ZIP02025

CountyNorfolk County

How does Cohasset Water Dept compare with other water systems in Norfolk County?

By EPA's size categories, Cohasset Water Dept is a medium system (3,301 to 10,000 people). Norfolk County has 58 active public water systems. Its population served is about half of the county average of 14,602 people per system, and accounts for 0.9% of the 846,897 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 Cohasset Water Dept is about 13% 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. Massachusetts has 531 active community water systems, 32% of the state's 1,636 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 76 Massachusetts systems (4.6%) list surface water as their primary source.

Who owns and regulates Cohasset Water Dept?

EPA lists Cohasset Water Dept 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. 30 of the 58 active systems in Norfolk County (52%) are also owned by a local government.

Does Cohasset Water Dept have drinking water violations?

Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2022. The violations listed here began between April 2021 and July 2022. By type: 11 monitoring and reporting and 1 public notice, recordkeeping or other. The contaminants or rules involved are Consumer Confidence Rule, Interim Enhanced Surface Water Treatment Rule, Endothall and Oxamyl. EPA lists 11 as archived and 1 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
2022-07-01	Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71	Consumer Confidence Rulecode 7000	No	Resolved
2021-06-01	Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38	Interim Enhanced Surface Water Treatment Rulecode 0300	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Endothallcode 2033	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Oxamylcode 2036	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Ethylene dibromide (EDB)code 2946	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Pentachlorophenolcode 2326	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Dinosebcode 2041	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Di(2-ethylhexyl) phthalatecode 2039	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Diquatcode 2032	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Hexachlorobenzenecode 2274	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Hexachlorocyclopentadienecode 2042	No	Archived
2021-04-01	Monitoring and reportingMonitoring, Regular · code 03	Heptachlor epoxidecode 2067	No	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.

Cohasset Water Dept: frequently asked questions

Who runs Cohasset Water Dept?

Cohasset Water Dept (PWSID MA4065000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.

How many people does Cohasset Water Dept serve?

Cohasset Water Dept reports serving 7,555 people through 2,692 service connections in Norfolk County, Massachusetts.

Where does Cohasset Water Dept 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 Cohasset Water Dept have any drinking water violations?

Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2022. 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 Cohasset Water Dept'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, none is health-based, and the most recent began in July 2022. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.

Where can I find Cohasset Water Dept's water quality report?

As a community water system, Cohasset Water Dept 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 Norfolk County

Water system	County	Population served	Type	Source
Quincy Water Dept. (MWRA)	Norfolk	106,000	Community	Purchased surface water
Brookline Water and Sewer Division	Norfolk	63,191	Community	Purchased surface water
Weymouth Water Department	Norfolk	57,871	Community	Surface water
Randolph/Holbrook Joint Water Board	Norfolk	46,519	Community	Surface water
Dedham Westwood Water Dist.	Norfolk	41,630	Community	Purchased surface water
Braintree Water and Sewer Dept.	Norfolk	39,143	Community	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, “Cohasset Water Dept, PWSID MA4065000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/cohasset-water-dept-ma4065000 (data as of October 1, 2026).