Reservoir · Larimer County · CO
Is North Poudre Reservoir Number 15 safe to swim?
No advisory or algae bloom reported for this water today.
Updated July 20, 2026 · EPA CyAN satellite
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Know before you get in at North Poudre Reservoir Number 15.
Get an alert the day a bacteria or algae advisory goes up.
What's in the water at North Poudre Reservoir Number 15 right now
As of July 20, 2026, North Poudre Reservoir Number 15 in Larimer 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 North Poudre Reservoir Number 15
North Poudre Reservoir Number 15 is a reservoir in Larimer County, Colorado covering about 0.5 sq mi, the 98th-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 North Poudre Reservoir Number 15
From EPA CyAN's satellite archive
Over 7 summers of satellite monitoring since 2020, North Poudre Reservoir Number 15 has reached blue-green algae advisory levels in 1 of them, most recently in August 2020. Blooms here have been occasional rather than annual. Its highest recorded reading was 299,353 cells/mL in August 2020.
Frequently asked: swimming in North Poudre Reservoir Number 15
- Is it safe to swim in North Poudre Reservoir Number 15 right now?
- North Poudre Reservoir Number 15 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 North Poudre Reservoir Number 15 have blue-green algae (cyanobacteria)?
- No blue-green algae bloom is detectable at North Poudre Reservoir Number 15 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 North Poudre Reservoir Number 15?
- No bloom is detected at North Poudre Reservoir Number 15 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 North Poudre Reservoir Number 15 have blue-green algae blooms?
- Over 7 summers of satellite monitoring since 2020, North Poudre Reservoir Number 15 has reached blue-green algae advisory levels in 1 of them, most recently in August 2020. Blooms here have been occasional rather than annual. Its highest recorded reading was 299,353 cells/mL in August 2020.
- 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 North Poudre Reservoir Number 15'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 North Poudre Reservoir Number 15, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.