Is Upper Russell Pond safe to swim?

As of July 22, 2026, Upper Russell Pond in Piscataquis County, Maine is not recommended for swimming. Satellite imagery measured 471,306 cells/mL of blue-green algae on July 18, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.2 in, which can wash bacteria and nutrients into the water.

How this read is built

Upper Russell Pond is a pond in Piscataquis County, Maine covering about 0.4 sq mi, the 310th-largest of the 319 lakes SwimZone monitors in Maine. Satellite imagery measured 471,306 cells/mL of blue-green algae on July 18, 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, Upper Russell Pond 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 855,112 cells/mL in August 2020.

It is currently peak season for blue-green algae, when warm, calm water lets blooms form fastest. This lake has bloomed in most monitored summers (7 of 7), historically peaking around August. Early summer, before the water fully warms, has generally been the safer window here; check the current read before you go either way.

Is it safe to swim in Upper Russell Pond right now?

Upper Russell Pond is not recommended for swimming today. Satellite imagery measured 471,306 cells/mL of blue-green algae on July 18, 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 Upper Russell Pond have blue-green algae (cyanobacteria)?

Yes. Satellite monitoring measured 471,306 cells/mL of blue-green algae (cyanobacteria) at Upper Russell Pond on July 18, 2026, above the 100,000 cells/mL advisory level. Avoid swimming and keep children and pets out of the water.

Can dogs swim in Upper Russell Pond?

No. Blue-green algae at Upper Russell Pond is above the safe-contact threshold (471,306 cells/mL on July 18, 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 Upper Russell Pond have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Upper Russell Pond 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 855,112 cells/mL in August 2020.

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

Today, 15 Maine waters are above a safe-contact threshold and 33 more warrant caution, out of 457 monitored waters SwimZone tracks in the state.

How is Upper Russell Pond'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 Upper Russell Pond, and a recent-rainfall overlay, all refreshed daily. It was last updated July 22, 2026.

• Blue-green algae and dogs→
• What does blue-green algae look like?→
• When is algae season?→