New York
Toxic algae in Greene County lakes
5 lakes and waterways in Greene County have harmful algal bloom reports in New York's official data. The most recent entry is for Sleepy Hollow Lake: Sleepy Hollow Lake was on New York's harmful algal bloom list from 6 August 2025 to 14 August 2025, with confirmed bloom status (2 reports). Sleepy Hollow Lake has 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.
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.
- Catskill Creek 2025
- Coxsackie Reservoir 2017
- Hollister Lake 2017
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.