March 24, 2024

Avoid Contact with the Charles River in Cambridge Due to Potential Harmful Bacteria and Other Pollutants Until March 25, 2024

Public Warning in effect until 10:47 p.m., March 25, 2024

People and pets should avoid contact with the lower Charles River from March 25, 2024 due to the release of stormwater mixed with sewage into the river.

The release of mixed stormwater and sewage—known as a “combined sewer overflow (CSO)”—is needed to prevent contaminated water from backing up into homes, businesses, and city streets.

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. For discharges that lasted less than two hours in the Cambridge area, please visit Cambridge Department of Public Works, City of Somerville, and Massachusetts Water Resources Authority’s websites.

One CSO release occurred on March 23, 2024 between Magazine Park and the Boston University Bridge (MWR201 – Cottage Farm). It began at 8:30 p.m. and ended at 10:47 p.m. This warning is in effect until 10:47 p.m., March 25, 2024.  

The impacted areas of the Charles River may include the Cambridge and Boston sides of the river just upstream of the Boston University Bridge to the Mass. Ave. Bridge.

The public should avoid contact with impacted areas of the river for 48 hours from the time the overflow ends because of increased health risks due to bacteria or other pollutants carried by the stormwater, such as fertilizers or pesticides. Contact with this water can make you and your pets sick. Avoid paddle boarding, boating, fishing, or other activities that can bring you in close contact with this water. 

Information about Cambridge CSO events are posted on the Cambridge Department of Public Works website.  Additional information is available on the Massachusetts Water Resources Authority and City of Somerville’s websites. Translations of the web pages are available using the translate box along the top of the websites.

The City of Cambridge continues to make major improvements to the city’s sewer and stormwater systems. As a result, there are fewer CSO events than in the past, but they still occur after heavy rain. To learn more, please visit:

The state law requiring public notification of sewage discharges into waterways took effect in 2022. Environmental groups advocated for the law because they were concerned that Massachusetts had no system in place to alert residents when sewage discharges occurred and what people could do to avoid illness. The new law requires municipalities to alert residents in multiple ways when discharges occur and to make the information available in other languages.

If you have questions about potential health risks from contaminated water, contact Sam Lipson at the Cambridge Public Health Department at [email protected] or 617-665-3838.

Translated Information

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ለበለጠ መረጃ፣ እባክዎን ድህረ ገጾቹን ይጎብኙ። በቀኝ በኩል በላይኛው ጥግ ላይ ያለውን “Translate” የሚለውን ሳጥን ይፈልጉ እና ቋንቋዎን ይምረጡ

Haitian Kreyòl 

Pou plis enfòmasyon, tanpri vizite sit entènèt sa yo. Jwenn bwat “Translate” nan kwen anwo dwat epi chwazi lang ou.


Para mais informações, visite esses sites. Encontre a caixa “Translate” no canto superior à direita e selecione seu idioma.


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