Is John Redmond Reservoir safe to swim?

As of July 20, 2026, John Redmond Reservoir in Coffey County, Kansas 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.

How this read is built

John Redmond Reservoir is a reservoir in Coffey County, Kansas covering about 12.9 sq mi, the 6th-largest of the 28 lakes SwimZone monitors in Kansas. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Larger, warmer waters like this can hold a bloom for weeks once nutrients and calm weather line up.

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, John Redmond Reservoir has reached blue-green algae advisory levels in 4 of them, most recently in July 2024. Its highest recorded reading was 543,129 cells/mL in August 2021.

Is it safe to swim in John Redmond Reservoir right now?

John Redmond 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 John Redmond Reservoir have blue-green algae (cyanobacteria)?

No blue-green algae bloom is detectable at John Redmond 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 John Redmond Reservoir?

No bloom is detected at John Redmond 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 John Redmond Reservoir have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, John Redmond Reservoir has reached blue-green algae advisory levels in 4 of them, most recently in July 2024. Its highest recorded reading was 543,129 cells/mL in August 2021.

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

Today, 10 Kansas waters are above a safe-contact threshold and 1 more warrant caution, out of 30 monitored waters SwimZone tracks in the state.

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