Cohasset Water Department
EPA ID: MA4065000 · 7,555 people served · 3 ZIP codes
Within the EPA compliance database, Cohasset Water Department shows 2 violations still pending resolution — a status that applies across the full service territory of approximately 7,555 people and reflects findings that have not yet cleared the federal enforcement process or received formal closure.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Cohasset Water Department Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Cohasset Water Department serves a community with a median household income of $187,060 and an estimated 8,358 residents across its service area. Approximately 75% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Cohasset Water Department's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 1% of homes in Norfolk County, Massachusetts rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 63th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How Cohasset Water Department compares to EPA limits
What This Means For You
Contaminant 2051 at 1 mg/L exceeds the EPA maximum of mg/L.
Surface Water Treatment Rule at 1 mg/L exceeds the EPA maximum of mg/L.
Fecal Coliform at 1 presence exceeds the EPA maximum of presence.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 6 detections recorded. 2 exceed federal EPA limits (4 ppt for PFOA/PFOS).
Comparable Water Systems
Similar-sized systems in Massachusetts
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Cohasset Water Department (EPA ID: MA4065000) is a community water system in Massachusetts that serves approximately 7,555 people from surface water sources.
This system provides water to 3 ZIP codes across 3 communities.
Average Home Safety Score: C (60/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Contaminant 2051 | Other Violation | 1 | No |
| Surface Water Treatment Rule | Treatment Failure | 1 | No |
| Fecal Coliform | Microbiological | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 02025 | 0.002 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 1 ZIP code confirmed via EPA Community Water System Service Area Boundaries v3 plus 2 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Cohasset Water Department (MA4065000) on EPA.gov.
Frequently Asked Questions
Is Cohasset Water Department water safe to drink?
Cohasset Water Department has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Cohasset Water Department serve?
Cohasset Water Department serves approximately 7,555 people across 3 ZIP codes in Massachusetts.
Where does Cohasset Water Department get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from Cohasset Water Department Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: Cohasset Water Department Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
The Massachusetts Department of Environmental Protection (MassDEP) prepared source water assessments in 2004. A susceptibility ranking of high was assigned to this system. Potential contamination sources identified include transport corridor risks and other hazards.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Watershed exposure sources reported
Land-use and natural conditions identified in the utility's source-water assessment as potential contamination sources upstream of treatment.
Treatment classification and chemical list sourced from Cohasset Water Department Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Federal UCMR5 PFAS Monitoring: Detected
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). PFAS compounds were detected below the current state-enforceable MCL.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
PFAS Substances Detected in This System
This water system's Consumer Confidence Report disclosed the following PFAS compounds. Levels are from the utility's most recent reporting cycle.
In April 2024, EPA finalized the first National Primary Drinking Water Regulation for six PFAS. Public water systems have until 2029 to comply. EPA — PFAS regulation overview →
Source: Consumer Confidence Report disclosed by Cohasset Water Department.
ZipCheckup is not affiliated with this water utility. PFAS detection data is sourced from public Consumer Confidence Reports filed by the utility itself.
Lead Service Line Inventory
Utility-reported lead service line presence and tap-sample lead level under federal LCRI requirements:
Below federal action level (0.015 mg/L)
MassDEP reports utility-level presence flag and tap-sampling without per-line breakdown. Customers should inquire with the utility about service line material at a specific address.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: MassDEP LCRR Service Line Inventory · Submitted 2024
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Cohasset Water Department (EPA ID: MA4065000) — request the latest Consumer Confidence Report or ask about specific contaminants.