Is Irondequoit Bay safe to swim?

As of July 22, 2026, Irondequoit Bay in Monroe County, New York is clear to swim. Satellite imagery measured 9,671 cells/mL of blue-green algae on July 21, 2026, well below the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 2.5 in, which can wash bacteria and nutrients into the water.

How this read is built

Irondequoit Bay is a lake in Monroe County, New York covering about 2.6 sq mi, the 45th-largest of the 133 lakes SwimZone monitors in New York. Satellite imagery measured 9,671 cells/mL of blue-green algae on July 21, 2026, well below the 100,000 cells/mL advisory threshold.

Blue-green algae (cyanobacteria) blooms are most common from midsummer into early fall, when the water is warm, calm, and rich in nutrients from runoff. They can produce toxins that make people sick and can be rapidly fatal to dogs, so skip water that looks green, scummy, or like spilled paint, and keep children and pets out of it.

Over 7 summers of satellite monitoring since 2020, Irondequoit Bay has reached blue-green algae advisory levels in 3 of them, most recently in July 2025. Its highest recorded reading was 957,862 cells/mL in June 2024.

Is it safe to swim in Irondequoit Bay right now?

Irondequoit Bay is clear to swim today. Satellite imagery measured 9,671 cells/mL of blue-green algae on July 21, 2026, well below the 100,000 cells/mL advisory threshold. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

Does Irondequoit Bay have blue-green algae (cyanobacteria)?

Low levels. Satellite monitoring measured 9,671 cells/mL at Irondequoit Bay on July 21, 2026, below the 100,000 cells/mL advisory threshold. Keep an eye out for surface scum, which can concentrate quickly.

Can dogs swim in Irondequoit Bay?

No bloom is detected at Irondequoit Bay today, but dogs are much more vulnerable to blue-green algae than people, and blooms can form within hours. Always keep dogs away from water that looks green, scummy, or discolored, and rinse them off after swimming.

How often does Irondequoit Bay have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Irondequoit Bay has reached blue-green algae advisory levels in 3 of them, most recently in July 2025. Its highest recorded reading was 957,862 cells/mL in June 2024.

How many New York lakes and beaches are unsafe for swimming today?

Today, 12 New York waters are above a safe-contact threshold and 188 more warrant caution, out of 495 monitored waters SwimZone tracks in the state.

How is Irondequoit Bay's water quality measured?

SwimZone builds this read from EPA CyAN satellite imagery for blue-green algae, official beach and fecal-bacteria advisories where a program monitors Irondequoit Bay, and a recent-rainfall overlay, all refreshed daily. It was last updated July 22, 2026.