Public water system · MA4221000
ActiveOak Bluffs Water District
At a glance
Oak Bluffs Water District (PWSID MA4221000) is an active community water system in Dukes County, Massachusetts. It reports serving 24,000 people through 4,628 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, 3 are health-based, and the most recent began in July 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
24,000
Service connections
4,628
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Oak Bluffs Water District compare with other water systems in Dukes County?
By EPA's size categories, Oak Bluffs Water District is a large system (10,001 to 100,000 people). Dukes County has 25 active public water systems, and Oak Bluffs Water District is the largest of them by population served. Its population served is about 14 times the county average of 1,687 people per system, and accounts for 57% of the 42,176 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 Oak Bluffs Water District is about 3.6 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 Oak Bluffs Water District?
EPA lists Oak Bluffs Water District 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. 10 of the 25 active systems in Dukes County (40%) are also owned by a local government.
Does Oak Bluffs Water District have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in July 2015. The violations listed here began between October 2010 and July 2015. By type: 8 monitoring and reporting, 3 contaminant level above the legal limit and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 12 as resolved. 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 |
|---|---|---|---|---|
| 2015-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2014-08-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2013-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloropropanecode 2983 | No | Resolved |
| 2010-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | cis-1,2-Dichloroethylenecode 2380 | No | Resolved |
| 2010-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2,4-Trichlorobenzenecode 2378 | No | Resolved |
| 2010-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2010-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1-Dichloroethylenecode 2977 | No | Resolved |
| 2010-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | o-Dichlorobenzenecode 2968 | No | Resolved |
| 2010-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Ethylbenzenecode 2992 | No | 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.
Oak Bluffs Water District: frequently asked questions
Who runs Oak Bluffs Water District?
Oak Bluffs Water District (PWSID MA4221000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Oak Bluffs Water District serve?
Oak Bluffs Water District reports serving 24,000 people through 4,628 service connections in Dukes County, Massachusetts.
Where does Oak Bluffs Water District 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 Oak Bluffs Water District have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in July 2015. 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 Oak Bluffs Water District'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, 3 are health-based, and the most recent began in July 2015. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.
Where can I find Oak Bluffs Water District's water quality report?
As a community water system, Oak Bluffs Water District 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 Dukes County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Edgartown Water Department | Dukes | 8,027 | Community | Groundwater |
| Tisbury Water Works | Dukes | 6,082 | Community | Groundwater |
| Menemsha Water Company | Dukes | 841 | Community | Groundwater |
| Marthas Vineyard Airport | Dukes | 750 | Non-transient non-community | Purchased groundwater |
| Gosnold Water Dept | Dukes | 425 | Community | Groundwater |
| West Tisbury Elementary School | Dukes | 375 | Non-transient non-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, “Oak Bluffs Water District, PWSID MA4221000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/oak-bluffs-water-district-ma4221000 (data as of October 1, 2026).