Cohasset Wastewater Treatment Facility
Cohasset, MA · Norfolk County · Publicly Owned Treatment Works
- Average flow
- 0.21 MGD
- Design flow
- —
- NPDES permit
- MAG580033
- Effective
- Permit expires
- November 2026
- Population served
- 4,646
- CWNS 2022
Cohasset Wastewater Treatment Facility is a publicly owned wastewater treatment works in Cohasset, Norfolk County, Massachusetts treating an average of 0.21 million gallons per day, serving about 4,646 residents. Treatment on site includes biological n removal, biological treatment, other, biosolids aerobic digestion, biosolids thickening, disinfection, uv and other unit processes. It discharges under NPDES permit MAG580033 (effective), which expires in November 2026, with 66 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Biological N removal
unit processBiological Treatment, Other
unit processBiosolids Aerobic Digestion
unit processBiosolids Thickening
unit processDisinfection, UV
unit processDisinfection, other chemical
unit processFiltration
unit processMicrofiltration (MF)
unit processScreening
unit processUnlock exact unit counts →
Compliance snapshot (last 3 years)
- Total violations
- 66
- Effluent violations
- 56
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
17 verified contacts for Cohasset Wastewater Treatment Facility, with validated emails and direct phone numbers.
Unlock 17 verified contacts (14 more than shown)
Names, validated emails and direct phone numbers for decision-makers at Cohasset Wastewater Treatment Facility, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Massachusetts
Hull · 7 mi away
1.03 MGD
Rockland · 10 mi away
2 MGD
Winthrop · 11 mi away
233.7 MGD
Brockton · 17 mi away
9.9 MGD
Salem · 20 mi away
17.57 MGD
Bridgewater · 21 mi away
0.15 MGD
Plymouth · 23 mi away
1.31 MGD
Manchester · 23 mi away
0.29 MGD
Cohasset Wastewater Treatment Facility: frequently asked questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed September 11, 2026; facility record last updated September 23, 2025.