New York
Toxic algae in Ontario County lakes
7 lakes and waterways in Ontario County have harmful algal bloom reports in New York's official data. The most recent entry is for Canandaigua Lake: Canandaigua Lake was on New York's harmful algal bloom list from 28 July 2025 to 2 November 2025, with confirmed bloom status (73 reports). Canandaigua Lake, Honeoye Lake and Canadice Lake 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.
- Castle Creek 2024
- Fairport Reservoir 2022
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.