Public water system · MA4055000
ActiveChatham Water Department
At a glance
Chatham Water Department (PWSID MA4055000) is an active community water system in Barnstable County, Massachusetts. It reports serving 30,000 people through 7,284 service connections. Its primary water source is groundwater, 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 July 2019.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
30,000
Service connections
7,284
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Chatham Water Department compare with other water systems in Barnstable County?
By EPA's size categories, Chatham Water Department is a large system (10,001 to 100,000 people). Barnstable County has 125 active public water systems. Its population served is about 6 times the county average of 5,016 people per system, and accounts for 4.8% of the 627,054 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 Chatham Water Department is about 4.5 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. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,354 Massachusetts systems (83%) list groundwater as their primary source.
Who owns and regulates Chatham Water Department?
EPA lists Chatham Water Department 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. 31 of the 125 active systems in Barnstable County (25%) are also owned by a local government.
Does Chatham Water Department have drinking water violations?
Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in July 2019. The violations listed here began between July 2006 and July 2019. By type: 10 contaminant level above the legal limit and 2 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (11 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 |
|---|---|---|---|---|
| 2019-07-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2015-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2015-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-05-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2012-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2008-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2008-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | 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.
Chatham Water Department: frequently asked questions
Who runs Chatham Water Department?
Chatham Water Department (PWSID MA4055000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Chatham Water Department serve?
Chatham Water Department reports serving 30,000 people through 7,284 service connections in Barnstable County, Massachusetts.
Where does Chatham Water Department get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Chatham Water Department 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 July 2019. 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 Chatham Water Department'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 July 2019. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.
Where can I find Chatham Water Department's water quality report?
As a community water system, Chatham Water Department 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 Barnstable County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Falmouth Water Dept | Barnstable | 97,551 | Community | Surface water |
| Dennis Water District | Barnstable | 65,000 | Community | Groundwater |
| Upper Cape Regional Water Cooperative | Barnstable | 56,250 | Community | Groundwater |
| Centerville Osterville Marstons Mills Wd | Barnstable | 50,000 | Community | Groundwater |
| Harwich Water Department | Barnstable | 39,144 | Community | Groundwater |
| Yarmouth Water Department | Barnstable | 38,900 | Community | Groundwater |
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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, “Chatham Water Department, PWSID MA4055000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/chatham-water-department-ma4055000 (data as of October 1, 2026).