On August 5, 2022 the Brewster Health Department, in conjunction with a recommendation by the MA Department of Public Health, posted a Cyanobacteria Health Advisory at 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 algae bloom is present. For additional information, please visit https://www.mass.gov/guides/cyanobacterial-harmful-algal-blooms-cyanohabs-water or Cyanobacteria Monitoring on Cape Cod - Barnstable County (wpengine.com).