Public water system · MA2136000
ActiveHolliston Water Department
At a glance
Holliston Water Department (PWSID MA2136000) is an active community water system in Middlesex County, Massachusetts. It reports serving 15,139 people through 5,018 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, none is health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
15,139
Service connections
5,018
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Holliston Water Department compare with other water systems in Middlesex County?
By EPA's size categories, Holliston Water Department is a large system (10,001 to 100,000 people). Middlesex County has 204 active public water systems. Its population served is about 90% above the county average of 7,986 people per system, and accounts for 0.9% 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 Holliston Water Department is about 126% 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. 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 Holliston Water Department?
EPA lists Holliston 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. 66 of the 204 active systems in Middlesex County (32%) are also owned by a local government.
Does Holliston Water Department have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2024. The violations listed here began between October 2022 and October 2024. By type: 12 monitoring and reporting. The contaminant or rule involved most often is Lead and Copper Rule (2 of them). EPA lists 10 as resolved and 2 as addressed. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Addressed |
| 2023-04-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Addressed |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Pentachlorophenolcode 2326 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorocyclopentadienecode 2042 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Alachlor (Lasso)code 2051 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,4-Dcode 2105 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Oxamylcode 2036 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Polychlorinated biphenyls (PCBs), totalcode 2383 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Endothallcode 2033 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dibromo-3-chloropropane (DBCP)code 2931 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,4,5-TP (Silvex)code 2110 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Picloramcode 2040 | 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.
Holliston Water Department: frequently asked questions
Who runs Holliston Water Department?
Holliston Water Department (PWSID MA2136000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Holliston Water Department serve?
Holliston Water Department reports serving 15,139 people through 5,018 service connections in Middlesex County, Massachusetts.
Where does Holliston 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 Holliston Water Department 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 October 2024. 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 Holliston 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, none is health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.
Where can I find Holliston Water Department's water quality report?
As a community water system, Holliston 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 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, “Holliston Water Department, PWSID MA2136000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/holliston-water-department-ma2136000 (data as of October 1, 2026).