Sewer System & Discharge Notifications


Worcester DPW&P Sewer Operations is responsible for the operation and management of sewer infrastructure, which includes three components: the sanitary sewer system, the surface sewer or stormwater system and the combined sewer system.

The sanitary sewer system conveys wastewater (sewage) from homes and businesses to the Upper Blackstone wastewater treatment plant. The surface sewer or stormwater system collects rainfall from City streets and pipes it to the nearest waterway. The combined sewer system collects both sewage and stormwater and conveys it to the Upper Blackstone plant for treatment before it discharges to the Blackstone River.

Worcester's combined sewer system covers some 4 square miles of the City including downtown, Shrewsbury Street, Green Island and parts of Main South. Some of the oldest pipes in the City are combined sewers with many constructed of brick in the mid to late 1800's.

Some of these brick combined sewers are enormous with diameters up to 96 inches (8 feet). Decades ago, when heavy rains caused combined sewer overflows (CSOs), the mix of stormwater and sewage would flow untreated to the Blackstone River. In the 1980s, Worcester became one of the first cities in New England to construct a CSO treatment facility designed to provide some level of wastewater treatment to the combined sewer flow before it entered the River.

Overflow (CSO/SSO) Incidents

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The City of Worcester along with MassDEP recognizes the importance of notifying the public when untreated sewage flows into Massachusetts waters. In January 2021, Governor Charlie Baker signed An Act Promoting Awareness of Sewage in Public Waters into law. If you wish to be notified via email of Worcester CSO/SSO incidents please Sign Up Now!

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Within 2 hours of a combined sewer overflow (CSO) or certain sanitary sewer overflows (SSO), an email will be sent advising of the date, time and location of the overflow. Follow-up notifications will be emailed every 8 hours until the overflow stops. Notifications will be provided in English, Spanish and Vietnamese.

CSOs only occur at one location and enter the Blackstone River behind Walmart on Tobias Boland Way. CSOs are treated at the Quinsigamond Ave CSO Treatment Facility before being discharged to the underground Mill Brook conduit and then the Blackstone River. Treatment removes trash and solids and provides disinfection to kill bacteria. CSOs only happen during heavy or prolonged rains and typically occur 5 to 25 times per year.

SSOs can potentially occur anywhere in Worcester and are untreated. Depending on where the SSO is located, the affected lake, pond, river or stream will vary. The notification will advise as to which water bodies are impacted. SSOs requiring notification are uncommon and may happen a few times per year or even less frequently.

After a CSO or SSO occurs it is recommended that use of the waterway or water body for contact recreation like swimming, wading, fishing and boating be stopped for 48 hours. Sewage overflows may contain harmful bacteria and other pollutants that can make a person sick if ingested.

Most Recent Notifications

Overflow Treatment Facility

The Quinsigamond Ave Combined Sewer Overflow Treatment Facility (QACSOTF) functions as a sewer pumping station during dry periods or small rain storms when only sewage or sewage mixed with moderate amounts of runoff is flowing through the combined sewers.

The facility pumps this sewage to the Upper Blackstone plant for treatment. When heavy rains occur the facility switches to treatment mode. After treatment, the flow moves into the former Mill Brook, then eventually discharges into the Blackstone River. Since the QACSOTF discharges to the Blackstone River, it is regulated by the USEPA and MassDEP under the National Pollution Discharge Elimination System (NPDES) permitting program under the Clean Water Act.

Notification of Final CSO Public Notification Plan

The City of Worcester has prepared and submitted a Final Combined Sewer Overflow (CSO) Public Notification Plan to the Massachusetts Department of Environmental Protection (MassDEP). Any interested party can View the Plan. Written comments can be submitted until March 1, 2023. This is a period of 30 days after the date of publication in Vocero Hispano Newspaper. Submit written comments to MassDEP by email (preferred) to or by mail to 100 Cambridge St, Suite 900 Boston, MA 02114. Submit written comments to Worcester Department of Public Works & Parks by email to or by mail to Worcester DPW&P Sewer Operations, 20 East Worcester St., Worcester, MA 01604. This Public Notice is published in the Environmental Monitor and Vocero Hispano newspaper.


The DPW&P regularly evaluates cost-effective solutions to sewer-related problems facing the City of Worcester.

Options to reduce the amount of stormwater entering the combined sewer system were explored and the most cost-effective were identified in the 2004 CSO Long-term Control Plan. DPW&P also completed modifications to the old Mill Brook conduit upstream of the QACSOTF so that greater volumes of combined sewage can be stored underground for slow, controlled release to the QACSOTF.

A new Long-Term Control Plan is being developed starting in the next few months; updates on the new Plan will be provided on this website in the future.


Beach Resources

Beach Closure information is posted to the main City Website or the Beach Posting website:

Contact Information

Department of Public Works
20 East Worcester Street
Worcester, MA 01604

Accessible via WRTA Bus Line. View Schedules

Phone: 508-929-1300
Fax: 508-799-1448
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Office Hours:
Monday - Friday
9 a.m. - 4 p.m.

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Worcester 311
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8 a.m. - 5 p.m.
Phone: 311
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