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HABs Alert: Harmful Algal Blooms in Tompkins County

(Ithaca, N.Y., August 10, 2022) – Suspicious cyanobacteria blooms, commonly referred to as Harmful Algal Blooms (HABs), have been reported in the Tompkins County portion of Cayuga Lake and monitoring is occurring. Trained volunteers and local officials monitor over 60% of the county shoreline for HABs on a weekly basis during the summer. These blooms may be small in size and confined to specific areas of the shoreline and bays. Blooms are often transient, typically lasting only a few hours. Areas where blooms are not observed can continue to be used for recreational use.

The Tompkins County Health Department urges residents and visitors to beware of HABs. These blooms can occur in any calm body of water and may produce toxins that are harmful to people and animals. Do not drink the water and avoid contact with the water if it appears discolored or has an unpleasant odor. Do not allow pets to swim in water where suspicious cyanobacteria blooms are present. Hot weather and intense rain and runoff events can lead to an increase in the presence of HABs.

HABs data for Cayuga Lake indicate the occurrence of  blooms may increase in early September. Blooms tend to occur intermittently throughout the month of September and then subside in early October. These late summer blooms often have high levels of microcystin toxin and occur most frequently in the northern third of the lake.

HABs can also be present in smaller ponds. Residents who have private ponds should monitor their ponds for signs of blooms and avoid contact. Residents may contact Tompkins County Soil and Water Conservation District (SWCD) for guidance on pond management and a possible site visit to view the suspicious bloom.  If a private resident is interested in testing a bloom, please contact the Community Science Institute (607-257-6606) to determine testing options and fees.

Identifying HABs:

If contact occurs with suspicious HABs,

  • Rinse thoroughly with clean water to remove cyanobacteria. Rinse dogs that may have gone in the water, so they do not lick their coats. Click here for more information on the risks HABS present to dogs:
  • 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.

The Community Science Institute (CSI)), Cayuga Lake Watershed Network, and Discover Cayuga Lake lead a volunteer program to monitor the Cayuga Lake shoreline for HABs during the summer months. To stay alert to blooms occurring on Cayuga Lake, check the Cayuga Lake HABs Reporting Page on CSI’s website at:

The NYS Department of Environmental Conservation (NYSDEC) has a map of reported HABs across the State here:

The Tompkins County Health Department is your partner for a healthy community. Find us online at and follow us on Facebook at and on Twitter at @TompkinsHealth. Sign up to receive Health Department updates or other county announcements via email or text. 

For media inquiries, contact Samantha Hillson,, 607-274-6714

For health-related questions regarding drinking water or recreational water activities, contact the Environmental Health Division: 607-274-6688

For private ponds, contact the Soil and Water Conservation District: (607) 257-2340