Is Cheney Reservoir safe to swim?

As of July 20, 2026, Cheney Reservoir in Reno County, Kansas is not recommended for swimming. Satellite imagery measured 179,648 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.0 in, which can wash bacteria and nutrients into the water.

How this read is built

Cheney Reservoir is a reservoir in Reno County, Kansas covering about 15.3 sq mi, the 4th-largest of the 28 lakes SwimZone monitors in Kansas. Satellite imagery measured 179,648 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. 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, Cheney Reservoir has reached blue-green algae advisory levels in 6 of them, most recently in August 2025. This is a lake that blooms most summers. Its highest recorded reading was 985,424 cells/mL in September 2020.

Is it safe to swim in Cheney Reservoir right now?

Cheney Reservoir is not recommended for swimming today. Satellite imagery measured 179,648 cells/mL of blue-green algae on July 19, 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 Cheney Reservoir have blue-green algae (cyanobacteria)?

Yes. Satellite monitoring measured 179,648 cells/mL of blue-green algae (cyanobacteria) at Cheney Reservoir on July 19, 2026, above the 100,000 cells/mL advisory level. Avoid swimming and keep children and pets out of the water.

Can dogs swim in Cheney Reservoir?

No. Blue-green algae at Cheney Reservoir is above the safe-contact threshold (179,648 cells/mL on July 19, 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 Cheney Reservoir have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Cheney Reservoir has reached blue-green algae advisory levels in 6 of them, most recently in August 2025. This is a lake that blooms most summers. Its highest recorded reading was 985,424 cells/mL in September 2020.

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 Cheney 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 Cheney Reservoir, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.