New York
Toxic algae in Rockland County lakes
11 lakes and waterways in Rockland County have harmful algal bloom reports in New York's official data. The most recent entry is for Tomkins Lake: Tomkins Lake was on New York's harmful algal bloom list on 12 August 2025, with confirmed bloom status (1 report). Tomkins Lake, Lake Welch and Rockland Lake and 2 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.
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.
- Hackensack River 2022
- Swartwout Lake 2021
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.