BOSTON – January 13, 2024 – The following is a public health warning related to two recent sewage discharges, 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.  

• Boston Water and Sewer Commission Outfall BOS070 in the Fort Point Channel experienced a discharge or overflow that started on Saturday, January 13 at 7:45am and ended on Saturday, January 13 at 9:50am creating a potential public health risk. This event impacts the waters in the Fort Point Channel, Downtown, and Waterfront. This advisory will expire on January 15 at 9:50am, 48 hours after the overflow has ended.

• Massachusetts Water Resources Authority Outfall MWR203 in Charlestown at the Prison Point Facility experienced a discharge or overflow that started on Saturday, January 13 at 7:04am and ended on January 13 at 10:12am creating a potential public health risk. This event impacts the waters of the Inner Harbor. This advisory will expire on January 15 at 10:12am, 48 hours after the overflow has ended.

Note that these data are preliminary and may be revised and additional overflows associated with this weather event may be added to the Boston Water and Sewer Commission and Massachusetts Water Resources Authority websites. Check the Massachusetts Water Resources Authority website here and the Boston Water and Sewer Commission here for current updates. 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.  

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.  

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