Is CRUZ BAY safe to swim?

As of July 19, 2026, CRUZ BAY in St. John Island County, U.S. Virgin Islands is clear to swim. Blue-green algae are not currently monitored at this water. No fecal-bacteria advisory is posted (state beach program). Rainfall over the past week totaled 0.1 in, which can wash bacteria and nutrients into the water.

How this read is built

CRUZ BAY is a lake in St. John Island County, U.S. Virgin Islands. Blue-green algae are not currently monitored at this water.

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.

Is it safe to swim in CRUZ BAY right now?

CRUZ BAY is clear to swim today. Blue-green algae are not currently monitored at this water. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

Does CRUZ BAY have blue-green algae (cyanobacteria)?

Blue-green algae are not currently monitored at CRUZ BAY. Watch for green, blue-green, or paint-like scum and avoid the water if you see it.

Can dogs swim in CRUZ BAY?

No bloom is detected at CRUZ BAY 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 many U.S. Virgin Islands lakes and beaches have swim advisories today?

Today, none of the 44 monitored U.S. Virgin Islands waters SwimZone tracks are under a swim advisory.

How is CRUZ BAY'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 CRUZ BAY, and a recent-rainfall overlay, all refreshed daily. It was last updated July 19, 2026.