Belair Beach in Hingham has been closed to swimming, after tests showed high levels of bacteria in the water.
According to the Department of Public Health website, Belair Beach was closed on Wednesday with a bacteria count of 1,187 colony-forming units of bacteria per 100 milliliters of water.
Beaches with counts over 104 cfu/100 ml. are closed to swimming, due to risk of illness.
Typically, bacteria tests are done for the bacteria enterococcus, which is found in fecal matter. The bacteria is also found in the intestines of humans and animals.
The count at Belair Beach is the highest higher than it has ever been since 2003. Although high counts are typically caused by rainstorms, officials of Hingham's Board of Health office could not comment on why the count was so high this week.
Follow up tests were taken on Thursday afternoon, staff in the Health office said. They will be posted before the weekend to the Department of Public Health website.