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Harmful Algal Blooms (HABs) Notifications Page

The 2018 HABs Notification season has ended. DEC posts weekly notifications from late Spring - Fall. Please be aware that blooms may still occur throughout the year. Visit the HABs, FAQ, or Archive pages for additional information.

There may be waterbodies with blooms that have not been reported to the DEC.

From May - October, this page provides information about the status of waterbodies with HABs. This information is collected through the DEC Lake Classification and Inventory (LCI) Program, Citizen Statewide Lake Assessment Program volunteers, partner HABs monitoring programs and from public reports.

Blooms of other algae are not reported here. The Important things to Know About HABs advice provided below should be followed when blooms are encountered.

Regulated swimming beaches are monitored regularly and evaluated for the presence of HABs. For information about regulated swimming beaches contact your local health department.

DEC encourages the public to view the HABs Archive page to be aware of waterbodies that were listed on the Notification page in previous years.

For information about HABs on Lake Champlain, visit the Lake Champlain Committee monitoring page and the Vermont Department of Health's blue-green algae notification page (above two links leave DEC website.)

Bloom Status

DEC HABs Program staff use visual observations, digital photographs and laboratory sampling results to determine whether a bloom consists of cyanobacteria (also known as blue-green algae) or another type of algae. A waterbody with a bloom may have one of three statuses: Suspicious, Confirmed or Confirmed with High Toxins Bloom. Cyanobacteria are irritants to some people even if toxins are not present so all contact with the bloom should be avoided. Blooms may be present in all or part of a waterbody.

  • Suspicious Bloom: DEC staff determined that conditions fit the description of a cyanobacteria bloom (HAB), based on visual observations and/or digital photographs. Laboratory analysis has not been done to confirm if this is a HAB. It is not known if there are toxins in the water.
  • Confirmed Bloom: Water sampling results have confirmed the presence of a cyanobacteria HAB which may produce toxins or other harmful compounds.
  • Confirmed with High Toxins Bloom: Water sampling results have confirmed that there are toxins present in enough quantities to potentially cause health effects if people and animals come in contact with the water through swimming or drinking.

Extent of Bloom

The extent of the bloom is a rough estimate of the size of the bloom within the waterbody and is recorded by monitoring program staff or from public reports.

  • Small Localized: Bloom affects a small area of the waterbody, limited from one to several neighboring properties.
  • Large Localized: Bloom affects many properties within an entire cove, along a large segment of the shoreline, or in a specific region of the waterbody.
  • Widespread/Lakewide: Bloom affects the entire waterbody, a large portion of the lake, or most to all of the shoreline.
  • Open Water: Sample was collected near the center of the lake and may indicate that the bloom is widespread and conditions may be worse along shorelines or within recreational areas. Special precautions should be taken in situations when a Confirmed with High Toxins Bloom is reported with an Open Water extent because toxins are likely to be even higher in shoreline areas.

Important things to Know About HABs

  • If you see it - avoid it
  • People, pets and livestock should avoid contact with water that is discolored or has algae scums on the surface. Colors can include shades of green, blue-green, yellow, brown or red. If contact does occur, rinse thoroughly with clean water to remove algae.
  • Never drink untreated surface water, whether or not algae blooms are present. Untreated surface water may contain other bacteria, parasites or viruses, as well as cyanotoxins that could cause illness if consumed.
  • People not on public water supplies should not drink surface water during an algal bloom, even if it is treated, because in-home treatments such as boiling, disinfecting water with chlorine or ultraviolet (UV), and water filtration units do not protect people from HABs toxins.
  • Stop using water and seek medical attention immediately if symptoms such as vomiting, nausea, diarrhea, skin, eye or throat irritation, allergic reactions or breathing difficulties occur after drinking or having contact with blooms or untreated surface water.
  • Please report any health symptoms to your physician and NYS Department of Health at or your local health department.
  • For answers to other frequently asked questions go to the DEC HABs FAQ page.
  • If you suspect that you have seen a HAB or you, your family, or pet has been in contact with a bloom, please report the bloom to the DEC. Fill out and submit a Suspicious Algal Bloom Report Form (PDF, 782 KB). Email the completed form and, if possible, attach digital photos (close-up and landscape to show extent and location) of the suspected bloom to

For more information you contact your regional DEC office or:

DEC HABs Program Coordinator
Rebecca Gorney Ph.D., Division of Water
Phone: (518) 402-8179

Email the DEC HABs Program

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Sign up for MakingWaves the Division of Water's weekly email subscription service to receive updates on HABs in New York waterbodies. MakingWaves provides information about important water-related issues, events, and news. To subscribe to MakingWaves, Subscribe to GovDelivery. When you reach the topics page, check the MakingWaves box under the Water category.