Harmful Cyanobacterial Bloom Advisories in Massachusetts

Current as of October 6, 2026

This list includes waterbodies that have been reported to DPH by local, state and federal partners that manage or regulate the respective waterbody, including recreational waterbodies without swimming beaches.

Current List of Waterbodies

• Flax Pond/Clear Bottom Pond, Carver
• Chilmark Pond, Chilmark
• Squibnocket Pond, Chilmark
• Heritage Pond, East Longmeadow
• Skinequit Pond, Harwich
• Pine Grove Cemetery, Lynn
• Redd’s Pond, Marblehead
• Pontoosuc Lake, Pittsfield 
• Billington Sea, Plymouth
• Boot Pond, Plymouth
• Great South Pond, Plymouth
• Halfway Pond, Plymouth
• Ames Pond, Stoughton
• Ryder Pond, Truro
• Slough Pond, Truro
• Snow Pond, Truro
• Pratt Pond, Upton
• Hardy Pond, Waltham
• Dyer Pond, Wellfleet
• Great Pond, Wellfleet
• Lake Chauncy, Westborough
• Indian Lake, Worcester

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.