New York
Toxic algae in Madison County lakes
10 lakes and waterways in Madison County have harmful algal bloom reports in New York's official data. The most recent entry is for Cazenovia Lake: Cazenovia Lake was on New York's harmful algal bloom list from 29 September 2025 to 2 November 2025, with confirmed bloom status (2 reports). Cazenovia Lake, Gorton Lake and De Ruyter Reservoir and 6 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.
- Cazenovia Lake Confirmed bloom
- Gorton Lake Confirmed bloom
- De Ruyter Reservoir Confirmed bloom
- Tuscarora Lake Confirmed bloom
- Lake Moraine Confirmed bloom
- Madison Lake Confirmed bloom
- Hatch Lake Not listed in 2025
- Bradley Brook Reservoir Not listed in 2025
- Craine Lake Not listed in 2025
- Lebanon Reservoir Not listed in 2025
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.