Heavy rainfall on Monday was likely the reason several Island beaches were closed to swimming on Tuesday.

Seth’s Pond, Medeiros Cove at Sailing Camp Park in Oak Bluffs, and the pond at Lucy Vincent in Chilmark remained closed to swimming as of presstime last night, due to high bacteria counts.

Lambert’s Cove Beach was reopened on Wednesday. It too had been closed to swimming the day before, but the West Tisbury board of health retested the water at both Seth’s and Lambert’s Cove beaches after the regular weekly samples taken Monday came back as unsafe for swimming.

The tests showed levels of enterococci, an indicator bacteria, unacceptable under state health regulations. Children, the elderly and others who may have compromised immune systems are to be particularly cautious. The towns continue to take new samples to determine when it will be safe to swim again.