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Advisory

Advisory  Update: DCR Recreation Advisory: Cyanobacteria Bloom in the Charles River

Date: 08/28/2026

What: The Department of Public Health (DPH) has expanded the warning area for a cyanobacteria bloom present in the Charles River’s Lower Basin area in the cities of Boston and Cambridge, downstream from Harvard Bridge and now including the area of the MIT Boathouse. During a bloom, it is strongly advised that the public should not have contact with the water. Additionally, pet owners should keep their animals away from the shoreline to prevent them from ingesting the water. This area will be retested once conditions visibly improve to determine whether cyanobacteria levels have fallen within acceptable limits per DPH guidelines. For questions regarding cyanobacteria blooms, please contact DPH at (617) 624-5757 or visit the agency’s algae webpage. 

highlight of area

 Where: Charles River Lower Basin in the cities of Boston and Cambridge 

When: effective immediately – until further notice 

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