On Wednesday, June 19, 2024, the New Hampshire Department of Environmental Services (NHDES) identified the presence of cyanobacteria in Mascoma Lake during routine monitoring activities and issued a Cyanobacteria Warning. When NHDES issues a warning, lakes are resampled weekly until the bloom subsides. While the current cyanobacteria density does reach the health advisory level, our drinking water supply is under no present threat.

To ensure public safety, NHDES advises residents and visitors to Mascoma Lake to adhere to the following precautions:

• Do not wade or swim in the water, particularly in or near the vicinity of surface blooms.
• Refrain from drinking the lake water and avoid using it for domestic purposes.
• Prevent pets or livestock from entering or approaching the water, as they are particularly vulnerable to toxic cyanobacteria.

For more information, FAQs, and to report any sightings of a cyanobacteria bloom, you can contact NHDES through their website. For updated advisories, you can also visit their Healthy Swimming Mapper on their website.