Reservoir · Pueblo County · CO
Is Saint Charles Reservoir Number 3 safe to swim?
No advisory or algae bloom reported for this water today.
Updated July 20, 2026 · EPA CyAN satellite
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What's in the water at Saint Charles Reservoir Number 3 right now
As of July 20, 2026, Saint Charles Reservoir Number 3 in Pueblo County, Colorado is clear to swim. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Rainfall over the past week totaled 0.0 in, which can wash bacteria and nutrients into the water.
Blue-green algae at Saint Charles Reservoir Number 3
Saint Charles Reservoir Number 3 is a reservoir in Pueblo County, Colorado covering about 0.8 sq mi, the 63rd-largest of the 107 lakes SwimZone monitors in Colorado. 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 Saint Charles Reservoir Number 3
From EPA CyAN's satellite archive
Over 7 summers of satellite monitoring since 2020, Saint Charles Reservoir Number 3 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 Saint Charles Reservoir Number 3
- Is it safe to swim in Saint Charles Reservoir Number 3 right now?
- Saint Charles Reservoir Number 3 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 Saint Charles Reservoir Number 3 have blue-green algae (cyanobacteria)?
- No blue-green algae bloom is detectable at Saint Charles Reservoir Number 3 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 Saint Charles Reservoir Number 3?
- No bloom is detected at Saint Charles Reservoir Number 3 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 Saint Charles Reservoir Number 3 have blue-green algae blooms?
- Over 7 summers of satellite monitoring since 2020, Saint Charles Reservoir Number 3 has not reached a blue-green algae advisory level. Conditions can still change quickly, so check the current read before you swim.
- How many Colorado lakes and beaches are unsafe for swimming today?
- Today, 26 Colorado waters are above a safe-contact threshold and 3 more warrant caution, out of 113 monitored waters SwimZone tracks in the state.
- How is Saint Charles Reservoir Number 3'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 Saint Charles Reservoir Number 3, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.