Is Big Bear Lake safe to swim?

As of July 20, 2026, Big Bear Lake in Otsego County, Michigan is clear to swim. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Rainfall over the past week totaled 0.3 in, which can wash bacteria and nutrients into the water.

How this read is built

Big Bear Lake is a lake in Otsego County, Michigan covering about 0.5 sq mi, the 204th-largest of the 263 lakes SwimZone monitors in Michigan. Satellite imagery detected no blue-green algae bloom as of July 19, 2026.

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, Big Bear Lake has reached blue-green algae advisory levels in 7 of them, most recently in June 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,839,344 cells/mL in August 2022.

Is it safe to swim in Big Bear Lake right now?

Big Bear Lake is clear to swim today. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

Does Big Bear Lake have blue-green algae (cyanobacteria)?

No blue-green algae bloom is detectable at Big Bear Lake as of July 19, 2026 (below the satellite's roughly 10,000 cells/mL detection limit). Cyanobacteria can still appear within hours in warm, calm, nutrient-rich water, so look before you swim.

Can dogs swim in Big Bear Lake?

No bloom is detected at Big Bear Lake 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 Big Bear Lake have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Big Bear Lake has reached blue-green algae advisory levels in 7 of them, most recently in June 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,839,344 cells/mL in August 2022.

How many Michigan lakes and beaches are unsafe for swimming today?

Today, 47 Michigan waters are above a safe-contact threshold and 100 more warrant caution, out of 882 monitored waters SwimZone tracks in the state.

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