Department of Public Works Public Notification
Date: May 23, 2025
Subject: Public Notice – Sanitary Sewer Overflow at Westerly Wastewater Treatment Plant
In accordance with Massachusetts regulation 314 CMR 16.00, the City of Marlborough Department of Public Works is issuing a public notification regarding a sanitary sewer overflow (SSO) that occurred at the Westerly Wastewater Treatment Plant, located at 303 Boundary Street, Marlborough, MA.
Due to a temporary power loss and related equipment issues, partially treated wastewater was discharged from the plant’s outfall to the Assabet River between approximately 8:00 p.m. on May 22 and 7:00 a.m. on May 23. The volume of the discharge is currently under investigation and will be reported once confirmed.
As a precaution, residents are advised to avoid contact with the Assabet River and connected water bodies downstream of the plant for 48 hours following this notice, due to the potential presence of bacteria and other pollutants associated with partially treated wastewater.
Normal plant operations have been restored, and the system is being closely monitored to ensure ongoing compliance and environmental protection. Additional information will be posted to the City of Marlborough’s website as it becomes available.
For questions, please contact:
Christopher S. LaFreniere
Assistant Commissioner – Utilities
City of Marlborough Department of Public Works
Phone: 508-624-6910 x33103
Email: clafreniere@marlborough-ma.gov