Reservoir · Franklin County · TN
Is Woods Reservoir safe to swim?
No advisory or algae bloom reported for this water today.
Updated July 20, 2026 · EPA CyAN satellite
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What's in the water at Woods Reservoir right now
As of July 20, 2026, Woods Reservoir in Franklin County, Tennessee is clear to swim. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Rainfall over the past week totaled 3.5 in, which can wash bacteria and nutrients into the water.
Blue-green algae at Woods Reservoir
Woods Reservoir is a reservoir in Franklin County, Tennessee. 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 Woods Reservoir
From EPA CyAN's satellite archive
Over 7 summers of satellite monitoring since 2020, Woods Reservoir has reached blue-green algae advisory levels in 2 of them, most recently in August 2025. Blooms here have been occasional rather than annual. Its highest recorded reading was 207,025 cells/mL in September 2023.
Frequently asked: swimming in Woods Reservoir
- Is it safe to swim in Woods Reservoir right now?
- Woods 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 Woods Reservoir have blue-green algae (cyanobacteria)?
- No blue-green algae bloom is detectable at Woods 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 Woods Reservoir?
- No bloom is detected at Woods 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 Woods Reservoir have blue-green algae blooms?
- Over 7 summers of satellite monitoring since 2020, Woods Reservoir has reached blue-green algae advisory levels in 2 of them, most recently in August 2025. Blooms here have been occasional rather than annual. Its highest recorded reading was 207,025 cells/mL in September 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 Woods 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 Woods Reservoir, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.