Is Marlette Lake safe to swim?

As of July 20, 2026, Marlette Lake in Washoe County, Nevada is not recommended for swimming. Satellite imagery measured 1,892,270 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.1 in, which can wash bacteria and nutrients into the water.

How this read is built

Marlette Lake is a lake in Washoe County, Nevada covering about 0.6 sq mi, the 38th-largest of the 47 lakes SwimZone monitors in Nevada. Satellite imagery measured 1,892,270 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, Marlette Lake has reached blue-green algae advisory levels in 4 of them, most recently in June 2026. Its highest recorded reading was 2,119,644 cells/mL in August 2025.

Is it safe to swim in Marlette Lake right now?

Marlette Lake is not recommended for swimming today. Satellite imagery measured 1,892,270 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 Marlette Lake have blue-green algae (cyanobacteria)?

Yes. Satellite monitoring measured 1,892,270 cells/mL of blue-green algae (cyanobacteria) at Marlette Lake 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 Marlette Lake?

No. Blue-green algae at Marlette Lake is above the safe-contact threshold (1,892,270 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 Marlette Lake have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Marlette Lake has reached blue-green algae advisory levels in 4 of them, most recently in June 2026. Its highest recorded reading was 2,119,644 cells/mL in August 2025.

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

Today, 13 Nevada waters are above a safe-contact threshold and 1 more warrant caution, out of 50 monitored waters SwimZone tracks in the state.

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