Combined Sewer Overflow Health Alerts

PUBLIC HEALTH WARNING ISSUED RELATED TO RECENT SEWAGE DISCHARGE

BOSTON – June 27, 2024 – The following is a public health warning related to a recent sewage discharge, also known as a combined sewer overflow (CSO). State regulations require local public health departments to provide notice to the public when these discharges may create a risk to public health, including when a discharge lasts for more than two hours.  A combined sewer overflow occurs when a large storm overwhelms the combined sewerage system causing rainwater to mix with wastewater and discharge to a nearby water body. This prevents sewage backups into homes and businesses.  

The public is advised to avoid contact with affected water bodies for at least 48 hours after a sewage discharge or overflow, during rainstorms, and for 48 hours after rainstorms end, due to increased health risks from bacteria or other pollutants associated with urban stormwater runoff and discharges of untreated or partially treated wastewater. 

Massachusetts Water Resource Authority outfall MWR203 located on the Charles River at Prison Point/the Charles River Dam experienced a discharge or overflow that started on Wednesday, June 26, 2024 at 9:46 p.m. and ended on Thursday, June 27, 2024 at 2:12 a.m., creating a potential public health risk.  This event impacts the waters of the Charles River and Upper Inner Harbor.  This advisory will expire on Saturday, June 29, 2024 at 2:12 a.m., 48 hours after the overflow has ended.

Boston Water and Sewer Commission Outfall BOS070 located in the Fort Point Channel experienced a discharge of rainwater and untreated sewage waste on Wednesday June 26, 2024 at 9:15 p.m. and ended on Wednesday, June 26, 2024 at 11:25 p.m., creating a potential public health risk.  This event impacts the waters of Boston Harbor, Fort Point Channel, and downtown waterfront.  This advisory will expire on Friday, June 28, 2024 at 11:25 p.m., 48 hours after the overflow has ended.

Note that this data is preliminary and may be revised. Check the Massachusetts Water Resources Authority website here and the Boston Water and Sewer Commission here for current updates.   

  More information about CSOs and public health is available at www.boston.gov/cso.   

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Public Health Notifications

State regulations also require local public health departments to provide notice to the public when these discharges may create a risk to public health, including when a discharge lasts for more than two hours.