Community Water System · PWS MA4065000
Cohasset Water Dept
Cohasset, Massachusetts 02025 - drinking water served from surface water sources to 7,555 people, tracked in EPA SDWIS and UCMR5.
- 7,555
- People served
- 64
- EPA violations
- 3
- Health-based
- 5 PFAS
- UCMR5 result
The verdict
EPA records 64 drinking-water violations at Cohasset Water Dept, 5% of them health-based - above the Massachusetts per-system average, and UCMR5 testing detected 5 PFAS compounds.
- 64
- Total EPA violations on record
- 5%
- Health-based (MCL / treatment failure)
- 7,555
- People served by this system
- 5
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Cohasset Water Dept
Cohasset Water Dept is a local-owned community water system that delivers drinking water to 7,555 residents in Cohasset, Massachusetts (Norfolk County) through 2,692 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 64 total violations for this system , of which 3 (5%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 52 monitoring and reporting violations are on file. The most recent violation on record dates to 2022.
The most frequently cited contaminant at this system is Coliform (TCR), recorded in 7 violations (MR). Under EPA's UCMR5 PFAS monitoring program, 5 PFAS compounds were detected in samples collected from this system, with a maximum reported concentration of 7.3 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.
Across Massachusetts, EPA tracks 1,599 public water systems serving 10,332,845 people, with 73,886 cumulative violations and 7,389 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 46.2 violations. Statewide, 148 of 263 UCMR5-tested systems have reported PFAS detections (56.3%).
Cohasset Water Dept's 64 violations sit above the Massachusetts average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
5 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 2,692
- County
- Norfolk
- School/Daycare
- No
- MCL Violations
- 1
- Monitoring Violations
- 52
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 7 | 2012 |
| Endrin | MR | 3 | 2021 |
| Toxaphene | MR | 3 | 2021 |
| 2,4,5-TP | MR | 3 | 2021 |
| BHC-GAMMA | MR | 3 | 2021 |
| Methoxychlor | MR | 3 | 2021 |
| 2,4-D | MR | 3 | 2021 |
| Lead and Copper Rule | TT | 2 | 2008 |
| Consumer Confidence Rule | Other | 2 | 2022 |
| Lead and Copper Rule | MR | 2 | 2010 |
| Coliform (TCR) | Other | 2 | 2012 |
| Carbofuran | MR | 1 | 2021 |
| Chlordane | MR | 1 | 2021 |
| ETHYLENE DIBROMIDE | MR | 1 | 2021 |
| Heptachlor | MR | 1 | 2021 |
| Pentachlorophenol | MR | 1 | 2021 |
| Total Polychlorinated Biphenyls (PCB) | MR | 1 | 2021 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 1 | 2021 |
| Dalapon | MR | 1 | 2021 |
| Di(2-ethylhexyl) phthalate | MR | 1 | 2021 |
| Dinoseb | MR | 1 | 2021 |
| Diquat | MR | 1 | 2021 |
| HEXACHLOROBENZENE | MR | 1 | 2021 |
| Hexachlorocyclopentadiene | MR | 1 | 2021 |
| Simazine | MR | 1 | 2021 |
| Interim Enhanced Surface Water Treatment Rule | MR | 1 | 2021 |
| LASSO | MR | 1 | 2021 |
| Heptachlor epoxide | MR | 1 | 2021 |
| Atrazine | MR | 1 | 2021 |
| Picloram | MR | 1 | 2021 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 6 of 87 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFNA | 9/16/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 9/16/2025 | 4.60 ppt | 3.00 ppt | Detected |
| PFMBA | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 9/16/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDoA | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 9/16/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFOS | 9/16/2025 | 4.50 ppt | 4.00 ppt | Detected |
| PFHxS | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 9/16/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 9/16/2025 | 6.70 ppt | 4.00 ppt | Detected |
| HFPO-DA | 9/16/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 9/16/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| NEtFOSAA | 9/16/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 9/16/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 9/16/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| 8:2 FTS | 9/16/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 9/16/2025 | 7.30 ppt | 5.00 ppt | Detected |
| ADONA | 9/16/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 9/16/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 9/16/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 9/16/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 9/16/2025 | 4.00 ppt | 3.00 ppt | Detected |
| 6:2 FTS | 9/16/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 6/9/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 6/9/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 6/9/2025 | 4.90 ppt | 4.00 ppt | Detected |
| PFOS | 6/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 6/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBS | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 6/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 8:2 FTS | 6/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxS | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/9/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 6/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 6/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 6/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 6/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Cohasset Water Dept.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID MA4065000 on SDWISSource: EPA SDWIS Federal Reports Search
Massachusetts Drinking Water Authority
MassDEP, Drinking Water Program is the primacy agency that licenses and inspects Cohasset Water Dept under EPA-delegated authority.
Open MA regulator portalSource: MassDEP, Drinking Water Program
Violation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2022 | Consumer Confidence Rule | Other | 2 | SDWIS / MA4065000 / 7000 |
| 2021 | Endrin | MR | 3 | SDWIS / MA4065000 / 2005 |
| 2021 | Toxaphene | MR | 3 | SDWIS / MA4065000 / 2020 |
| 2021 | 2,4,5-TP | MR | 3 | SDWIS / MA4065000 / 2110 |
| 2021 | BHC-GAMMA | MR | 3 | SDWIS / MA4065000 / 2010 |
| 2021 | Methoxychlor | MR | 3 | SDWIS / MA4065000 / 2015 |
| 2021 | 2,4-D | MR | 3 | SDWIS / MA4065000 / 2105 |
| 2021 | Carbofuran | MR | 1 | SDWIS / MA4065000 / 2046 |
| 2021 | Chlordane | MR | 1 | SDWIS / MA4065000 / 2959 |
| 2021 | ETHYLENE DIBROMIDE | MR | 1 | SDWIS / MA4065000 / 2946 |
| 2021 | Heptachlor | MR | 1 | SDWIS / MA4065000 / 2065 |
| 2021 | Pentachlorophenol | MR | 1 | SDWIS / MA4065000 / 2326 |
| 2021 | Total Polychlorinated Biphenyls (PCB) | MR | 1 | SDWIS / MA4065000 / 2383 |
| 2021 | 1,2-DIBROMO-3-CHLOROPROPANE | MR | 1 | SDWIS / MA4065000 / 2931 |
| 2021 | Dalapon | MR | 1 | SDWIS / MA4065000 / 2031 |
How Cohasset Water Dept Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Cohasset Water Dept | Massachusetts avg | Federal benchmark |
|---|---|---|---|
| Total violations | 64 | 46.2 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 3 | 4.6 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | 5 compounds | 56.3% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 7,555 | 6,462 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,599 regulated public water systems in Massachusetts.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is Cohasset Water Dept water safe to drink? ▼
How many people does Cohasset Water Dept serve? ▼
What type of violations does Cohasset Water Dept have? ▼
Has PFAS been detected in Cohasset Water Dept water? ▼
What water source does Cohasset Water Dept use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.