Escherichia coli (E.coli) is the only member of the total coliform group of bacteria that is found only in the intestines of
mammals, including humans. The presence of E.coli in water indicates recent fecal contamination and may indicate
the possible presence of disease-causing pathogens, such as bacteria, viruses, and parasites. Although most strains of
E.coli bacteria are harmless, certain strains, such as E.coli 0157:H7, may cause illness