Is Joe Pool Lake safe to swim?

As of July 20, 2026, Joe Pool Lake in Dallas County, Texas is not recommended for swimming. Satellite imagery measured 365,109 cells/mL of blue-green algae on July 19, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 1.9 in, which can wash bacteria and nutrients into the water.

How this read is built

Joe Pool Lake is a lake in Dallas County, Texas covering about 10.2 sq mi, the 41st-largest of the 218 lakes SwimZone monitors in Texas. Satellite imagery measured 365,109 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, Joe Pool Lake 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 625,897 cells/mL in September 2025.

Is it safe to swim in Joe Pool Lake right now?

Joe Pool Lake is not recommended for swimming today. Satellite imagery measured 365,109 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 Joe Pool Lake have blue-green algae (cyanobacteria)?

Yes. Satellite monitoring measured 365,109 cells/mL of blue-green algae (cyanobacteria) at Joe Pool 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 Joe Pool Lake?

No. Blue-green algae at Joe Pool Lake is above the safe-contact threshold (365,109 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 Joe Pool Lake have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Joe Pool Lake 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 625,897 cells/mL in September 2025.

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

Today, 78 Texas waters are above a safe-contact threshold and 85 more warrant caution, out of 399 monitored waters SwimZone tracks in the state.

How is Joe Pool 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 Joe Pool Lake, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.