3 Cape Cod Freshwater Spots to Avoid Swimming at This Weekend

Cape Cod residents and weekend visitors heading to the water are being urged to check local pond conditions before swimming, as several freshwater spots remain under bacteria-related advisories. As of Friday, June 12, three Cape Cod swimming areas are listed under alert because of potential cyanobacteria concerns, according to the Association to Preserve Cape Cod, which monitors water quality across the region.

The affected locations are Bearse Pond and Hinckleys Pond in Barnstable, and Sheep Pond in Brewster. Each is marked “Potential for Concern,” indicating that conditions may not be safe for recreational swimming until further testing shows improvement.

Cyanobacteria, sometimes referred to as blue-green algae, can produce toxins that may pose health risks to people and animals. The Associated to Preserve Cape Cod warns that swimming in water with high levels of cyanobacteria and its toxins can lead to illness. The Centers for Disease Control and Prevention says symptoms from exposure can range from headache and fever to nausea and vomiting, and in more severe cases, can include liver damage.

The advisories come just as warm weather is expected to draw more people to Cape Cod’s ponds and freshwater beaches for the weekend. Health officials and environmental monitors are reminding swimmers that clear-looking water is not always safe. Cyanobacteria blooms can sometimes be difficult to detect without testing, and advisories are issued when samples indicate elevated levels or when conditions suggest a bloom may develop.

The APCC works with local, county, state and federal officials to monitor Cape Cod ponds for cyanobacteria. Testing is generally conducted twice a week, and water bodies remain under advisory until results show the water has returned to safer conditions. According to the organization’s standard practice, advisories or closures are usually lifted only after two consecutive tests, spaced one week apart, indicate safe bacteria levels.

Because pond conditions can change quickly, swimmers are encouraged to review the latest monitoring updates before heading out. The APCC maintains a cyanobacteria monitoring map that tracks the current status of Cape Cod ponds and provides information on which swimming spots are under watch, under alert, or considered safe.

For now, anyone planning a swim at a freshwater location on Cape Cod should pay close attention to posted warnings and avoid swimming in ponds currently listed under alert. The current advisories serve as a reminder that warm weather can bring increased recreational use of local waterways, but also a greater need for caution when bacteria levels rise.