Is Lake Pleasant safe to swim?

As of July 20, 2026, Lake Pleasant in Yavapai County, Arizona carries a swim caution. Satellite imagery measured 62,890 cells/mL of blue-green algae on July 19, 2026, elevated but below the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.7 in, which can wash bacteria and nutrients into the water.

How this read is built

Lake Pleasant is a lake in Yavapai County, Arizona covering about 14.4 sq mi, the 5th-largest of the 21 lakes SwimZone monitors in Arizona. Satellite imagery measured 62,890 cells/mL of blue-green algae on July 19, 2026, elevated but below the 100,000 cells/mL advisory threshold. Larger, warmer waters like this can hold a bloom for weeks once nutrients and calm weather line up.

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 Pleasant has reached blue-green algae advisory levels in 2 of them, most recently in June 2022. Blooms here have been occasional rather than annual. Its highest recorded reading was 957,862 cells/mL in September 2021.

Is it safe to swim in Lake Pleasant right now?

Lake Pleasant carries a swim caution today. Satellite imagery measured 62,890 cells/mL of blue-green algae on July 19, 2026, elevated but 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 Lake Pleasant have blue-green algae (cyanobacteria)?

Low levels. Satellite monitoring measured 62,890 cells/mL at Lake Pleasant on July 19, 2026, below the 100,000 cells/mL advisory threshold. Keep an eye out for surface scum, which can concentrate quickly.

Can dogs swim in Lake Pleasant?

Use caution. Blue-green algae at Lake Pleasant are elevated (62,890 cells/mL on July 19, 2026). Dogs are far more sensitive to cyanobacteria than people, so keep them out of the water and away from surface scum.

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

Over 7 summers of satellite monitoring since 2020, Lake Pleasant has reached blue-green algae advisory levels in 2 of them, most recently in June 2022. Blooms here have been occasional rather than annual. Its highest recorded reading was 957,862 cells/mL in September 2021.

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

Today, 3 Arizona waters are above a safe-contact threshold and 1 more warrant caution, out of 22 monitored waters SwimZone tracks in the state.

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