Is Reading House Slough safe to swim?

As of July 20, 2026, Reading House Slough in Lake County, Tennessee is not recommended for swimming. Satellite imagery measured 742,033 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.2 in, which can wash bacteria and nutrients into the water.

How this read is built

Reading House Slough is a lake in Lake County, Tennessee covering about 17.1 sq mi, the 7th-largest of the 20 lakes SwimZone monitors in Tennessee. Satellite imagery measured 742,033 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, Reading House Slough has reached blue-green algae advisory levels in 7 of them, most recently in July 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,308,648 cells/mL in June 2020.

Is it safe to swim in Reading House Slough right now?

Reading House Slough is not recommended for swimming today. Satellite imagery measured 742,033 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 Reading House Slough have blue-green algae (cyanobacteria)?

Yes. Satellite monitoring measured 742,033 cells/mL of blue-green algae (cyanobacteria) at Reading House Slough 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 Reading House Slough?

No. Blue-green algae at Reading House Slough is above the safe-contact threshold (742,033 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 Reading House Slough have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Reading House Slough has reached blue-green algae advisory levels in 7 of them, most recently in July 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,308,648 cells/mL in June 2020.

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

Today, 4 Tennessee waters are above a safe-contact threshold and 0 more warrant caution, out of 24 monitored waters SwimZone tracks in the state.

How is Reading House Slough'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 Reading House Slough, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.