Lake · Henderson County · TN

Is Dogwood Lake safe to swim?

Advisory

Blue-green algae is above the safe-contact threshold.

Updated July 20, 2026 · EPA CyAN satellite

Recent rain
8.3 in
Water type
Lake
Last updated
Jul 20
Bacteria
E. coli, fecal
Not monitored
Tested
Not monitored
Blue-green algae
cyanobacteria
Advisory
Tested
420,749
cells/mL
Advisory over
100,000
cells/mL
Sampled Jul 19 · EPA CyAN satellite

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What's in the water at Dogwood Lake right now

As of July 20, 2026, Dogwood Lake in Henderson County, Tennessee is not recommended for swimming. Satellite imagery measured 420,749 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 8.3 in, which can wash bacteria and nutrients into the water.

How this read is built

Blue-green algae at Dogwood Lake

Dogwood Lake is a lake in Henderson County, Tennessee. Satellite imagery measured 420,749 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold.

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 Dogwood Lake

From EPA CyAN's satellite archive

Over 7 summers of satellite monitoring since 2020, Dogwood Lake has reached blue-green algae advisory levels in 7 of them, most recently in June 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,385,042 cells/mL in August 2023.

Frequently asked: swimming in Dogwood Lake

Is it safe to swim in Dogwood Lake right now?
Dogwood Lake is not recommended for swimming today. Satellite imagery measured 420,749 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 Dogwood Lake have blue-green algae (cyanobacteria)?
Yes. Satellite monitoring measured 420,749 cells/mL of blue-green algae (cyanobacteria) at Dogwood Lake 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 Dogwood Lake?
No. Blue-green algae at Dogwood Lake is above the safe-contact threshold (420,749 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 Dogwood Lake have blue-green algae blooms?
Over 7 summers of satellite monitoring since 2020, Dogwood Lake has reached blue-green algae advisory levels in 7 of them, most recently in June 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,385,042 cells/mL in August 2023.
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 Dogwood Lake'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 Dogwood Lake, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.

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