New York
Toxic algae in Sullivan County lakes
24 lakes and waterways in Sullivan County have harmful algal bloom reports in New York's official data. The most recent entry is for Silver Lake: Silver Lake was on New York's harmful algal bloom list on 6 October 2025, with confirmed bloom status (1 report). Silver Lake, Evens Lake and Loch Sheldrake and 8 more have had blooms in three or more years.
Lakes with bloom history
Newest report first. Each lake has its own page with the full history and what the results mean.
- Silver Lake Confirmed bloom
- Evens Lake Confirmed bloom
- Loch Sheldrake Confirmed bloom
- Chestnut Ridge Pond Confirmed bloom
- Swinging Bridge Reservoir Confirmed bloom
- Yankee Lake Confirmed bloom
- Morningside Lake Confirmed bloom
- Lake Superior Not listed in 2025
- Pleasure Lake Not listed in 2025
- Mongaup Pond Not listed in 2025
- Fox Lake Not listed in 2025
- Mountain Lake Not listed in 2025
- Toronto Reservoir Not listed in 2025
- Montgomery Lake Not listed in 2025
- Wolf Lake Not listed in 2025
- Lake Huntington Not listed in 2025
Other waterbodies with a report
These have one or two reports in a single year, which isn't enough history for a page of their own yet.
- Indian Field Pond 2025
- Kiamesha Lake 2015
- Lake Anawanda 2013
- Lake Louise Marie 2021
- Lochada Lake 2022
- Swan Lake 2023
- White Lake 2022
- York Lake 2023
Source: New York State Department of Environmental Conservation (DEC), official data, checked 24 October 2026. For today's conditions see the NYHABS map. No report doesn't mean a lake is safe: most water is only tested occasionally.