Jackknife Harbor

Source Information

The Chatham County Department of Health and the Environment, and the Massachusetts Department of Conservation and Recreation collect water quality samples weekly from May through September. Samples are taken on Monday, and the results are posted by Wednesday. The water at marine beaches is tested for the presence of Enterococci, a group of bacterial species typically found in human and animal intestines and are therefore present in sewage. Enterococci is also referred to as indicator organisms. Indicator organisms are used to predict the presence of pathogenic, or disease-causing, organisms associated with fecal contamination. Swim Guide checks for the latest information daily, Monday - Friday during the swimming season (May through September). A beach is marked Green when less than 104 units of Enterococci / 100 ml of water is present in a single sample, or when the geometric mean of 5 samples contains less than 35 units / 100ml of water. A beach is marked Red when more than 104 units of Enterococci / 100 ml of water is present in a single sample, or when the geometric mean of 5 samples contains more than 35 units / 100ml of water. A beach is marked Grey when there is no current or reliable monitoring information available.