Is Lake Neatahwanta safe to swim?

As of July 20, 2026, Lake Neatahwanta in Oswego County, New York is not recommended for swimming. Satellite imagery measured 3,153,138 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.4 in, which can wash bacteria and nutrients into the water.

How this read is built

Lake Neatahwanta is a lake in Oswego County, New York covering about 1.2 sq mi, the 77th-largest of the 156 lakes SwimZone monitors in New York. Satellite imagery measured 3,153,138 cells/mL of blue-green algae on July 19, 2026, above 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, Lake Neatahwanta has reached blue-green algae advisory levels in 7 of them, most recently in July 2026. This is a lake that blooms most summers. Its highest recorded reading was 3,845,767 cells/mL in September 2021.

Is it safe to swim in Lake Neatahwanta right now?

Lake Neatahwanta is not recommended for swimming today. Satellite imagery measured 3,153,138 cells/mL of blue-green algae on July 19, 2026, above 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 Lake Neatahwanta have blue-green algae (cyanobacteria)?

Yes. Satellite monitoring measured 3,153,138 cells/mL of blue-green algae (cyanobacteria) at Lake Neatahwanta on July 19, 2026, above the 100,000 cells/mL advisory level. Avoid swimming and keep children and pets out of the water.

Can dogs swim in Lake Neatahwanta?

No. Blue-green algae at Lake Neatahwanta is above the safe-contact threshold (3,153,138 cells/mL on July 19, 2026). Cyanobacteria toxins can be rapidly fatal to dogs, which swallow it while swimming and lick it from their fur. Keep dogs out of the water and away from any scum along the shore.

How often does Lake Neatahwanta have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Lake Neatahwanta has reached blue-green algae advisory levels in 7 of them, most recently in July 2026. This is a lake that blooms most summers. Its highest recorded reading was 3,845,767 cells/mL in September 2021.

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

Today, 19 New York waters are above a safe-contact threshold and 148 more warrant caution, out of 520 monitored waters SwimZone tracks in the state.

How is Lake Neatahwanta'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 Lake Neatahwanta, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.