Harmful Cyanobacterial Bloom Advisories in Massachusetts current as of June 26, 2025

This list includes waterbodies that have been reported to DPH by local, state and federal partners that manage or regulate the respective waterbody.

  • Upper Mill Pond, Brewster
  • Rubber Thread Pond, Easthampton
  • Schoolhouse Pond, Hyannis
  • Clarks Cove, Nantucket
  • Capaum Pond, Nantucket
  • Lake Cochituate—Middle Pond, Natick
  • Lake Cochituate—Snake Brook, Natick
  • Hardy Pond, Waltham

Please note: This should not be considered a complete list of all advisories in Massachusetts. This list includes waterbodies that have been reported to DPH by local, state and federal partners that manage or regulate the respective waterbody. If you think an algal bloom may be present you are encouraged to avoid contact with the water — WHEN IN DOUBT, STAY OUT! To see examples of what algae blooms look like, please visit the Identifying cyanobacterial blooms and scums page.

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