New York
Toxic algae in Putnam County lakes
32 lakes and waterways in Putnam County have harmful algal bloom reports in New York's official data. The most recent entry is for Kirk Lake: Kirk Lake was on New York's harmful algal bloom list on 19 November 2025, with confirmed bloom status (1 report). Kirk Lake, Putnam Lake and Croton Falls Reservoir and 11 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.
- Kirk Lake Confirmed bloom
- Putnam Lake Confirmed bloom
- Croton Falls Reservoir Confirmed bloom
- Lake Tonetta Confirmed bloom
- Lake Carmel Confirmed bloom
- Secor Lake Confirmed bloom
- Barger Pond Confirmed bloom
- White Pond Confirmed bloom
- Lake Peekskill Confirmed bloom
- Roaring Brook Lake Confirmed bloom
- Bog Brook Reservoir Not listed in 2025
- Oscawana Lake Not listed in 2025
- Diverting Reservoir Not listed in 2025
- Cortlandt Lake Not listed in 2025
- Peach Lake Not listed in 2025
- Seven Hills Lake Not listed in 2025
- Lake Casse Not listed in 2025
- Barrett Pond Not listed in 2025
- Kentwood Lake Not listed in 2025
- Palmer Lake Not listed in 2025
- Indian Lake 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.
- China Pond 2017
- East Branch Reservoir 2024
- Herrlich Pond 2020
- Lake Celeste 2024
- Lake Macgregor 2020
- Lake Mahopac 2018
- Lake Tibet 2021
- Middle Branch Reservoir 2024
- Patterson Veterans Park Swim Pond 2014
- Sagamore Lake 2021
- Wiccopee Reservoir 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.