Cyanobacteria Advisory For Lower Mill Pond and Gristmill Dam


On September 13, 2022 the Brewster Health Department, per MA Department of Public Health Cyanobacteria in Recreational Water Board of Health Guidance 2022, posted a Cyanobacteria Health Advisory at the Lower Mill Pond Dam at the Gristmill location due to a visible algal bloom indicative of elevated levels of Cyanobacteria. As a precautionary measure, a second posting was erected at the Lower Mill Pond Beach Association kayak launch area through the collaborative efforts of the Brewster Ponds Coalition and the Beach Association. Testing of the pond will continue on a weekly basis to monitor existing cyanobacteria levels. Until further notice, people and pets should avoid contact with any pond water where a visible algal bloom is present. For additional information, please visit or Cyanobacteria Monitoring on Cape Cod - Barnstable County (