Reservoir · Windham County · VT
Is Somerset Reservoir safe to swim?
No advisory or algae bloom reported for this water today.
Updated July 20, 2026 · EPA CyAN satellite
SwimZone for iPhone · launching soon
Know before you get in at Somerset Reservoir.
Get an alert the day a bacteria or algae advisory goes up.
What's in the water at Somerset Reservoir right now
As of July 20, 2026, Somerset Reservoir in Windham County, Vermont is clear to swim. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Rainfall over the past week totaled 0.5 in, which can wash bacteria and nutrients into the water.
Blue-green algae at Somerset Reservoir
Somerset Reservoir is a reservoir in Windham County, Vermont covering about 2.4 sq mi, the 7th-largest of the 26 lakes SwimZone monitors in Vermont. 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.
Bloom history at Somerset Reservoir
From EPA CyAN's satellite archive
Over 7 summers of satellite monitoring since 2020, Somerset Reservoir has not reached a blue-green algae advisory level. Conditions can still change quickly, so check the current read before you swim.
Frequently asked: swimming in Somerset Reservoir
- Is it safe to swim in Somerset Reservoir right now?
- Somerset Reservoir 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 Somerset Reservoir have blue-green algae (cyanobacteria)?
- No blue-green algae bloom is detectable at Somerset Reservoir 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 Somerset Reservoir?
- No bloom is detected at Somerset Reservoir 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 Somerset Reservoir have blue-green algae blooms?
- Over 7 summers of satellite monitoring since 2020, Somerset Reservoir has not reached a blue-green algae advisory level. Conditions can still change quickly, so check the current read before you swim.
- How many Vermont lakes and beaches are unsafe for swimming today?
- Today, 3 Vermont waters are above a safe-contact threshold and 2 more warrant caution, out of 29 monitored waters SwimZone tracks in the state.
- How is Somerset Reservoir'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 Somerset Reservoir, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.