Just days before Independence Day celebrations, more than fifty beaches in the U.S. have been closed or placed under advisory due to elevated levels of bacteria in the water. This situation, which spans from California to Massachusetts including New York, Washington, Illinois, and Michigan has raised public health alarms just as families prepare to enjoy summer and the traditional Fourth of July holiday.

Federal authorities warn that the main culprit is usually Vibrio, a group of coastal bacteria that thrive in warm waters between May and October. According to the Centers for Disease Control and Prevention (CDC), infections caused by these bacteria known as vibriosis  can lead to diarrhea, vomiting, fever, and potentially serious complications, especially in individuals with open wounds, the elderly, or those with weakened immune systems.

In Long Island, New York, beaches such as Benjamin Beach, Ronkonkoma, and Sayville Marina Park remain closed due to bacterial levels far above safe health standards. In Massachusetts, nearly twenty beaches are closed including Pomps Pond (Andover), Mingo Beach (Beverly), and Magnolia Beach (Manchester), among others  due to the presence of bacteria and cyanobacteria in the water.

In California, several beaches in San Diego County and the Los Angeles area (including Santa Monica Pier and Venice Beach) have also been shut down or placed under advisory after exceeding permitted bacterial levels. Washington has issued “stay out” warnings for seven beaches in King County, while Illinois has issued advisories for 34 beaches, and Michigan has closed nine primarily due to runoff and wildlife contamination.

Public health experts warn that such alerts have not been common in previous summers and are mainly attributed to a combination of sudden rainfall, increased runoff from urban and agricultural areas, and unusually warm water temperatures. The presence of contaminants such as animal or human fecal matter promotes the spread of Enterococcus and Vibrio, markers of unsafe water.

What precautions should you take?

• Check before heading out: Visit local health department websites or check updated water quality dashboards.

• Avoid swimming in areas with warnings.

• Protect open wounds or avoid submerging them in water.

• If you develop gastrointestinal symptoms after swimming, seek medical attention promptly.

With over 80,000 estimated cases of vibriosis annually in the U.S., these bacteria represent a real and growing threat, especially during periods of intense heat. These beach closures should serve as a wake-up call to invest in water monitoring and sanitation, reduce runoff, and modernize health protocols ensuring safety for millions of beachgoers during the holiday season.