New York

Toxic algae in Suffolk County lakes

55 lakes and waterways in Suffolk County have harmful algal bloom reports in New York's official data. The most recent entry is for Big Reed Pond: Big Reed Pond was on New York's harmful algal bloom list on 30 September 2025, with confirmed bloom status (2 reports). Big Reed Pond, Coopers Neck Pond and Fort Pond and 28 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.

Deep Pond 2013
Division Pond 2014
Dog Ponds 2021
Donahues Pond 2023
Great Pond 2021
Hallocks Pond 2021
Halsey Neck Pond 2021
Lake Capri 2014
Lloyd Harbor Park Pond 2020
Mckay Pond 2015
Peconic River 2016
Phillips Pond 2025
Pond 2024
Sayre Pond 2017
Setauket Mill Pond 2016
Walden Pond 2022
Wildwood Lake 2018
Willow Pond 2020

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.