Bacteria that serve as indicators of pollution and pathogens when found in water. These are usually found in the intestinal tract of humans and other warm-blooded animals.Coliform bacteria are categorized as organisms that reside in the fecal matter of humans or animals throughout the world. Although coliform bacteria are unlikely to be responsible for illnesses, they do give signs of pathogens that could be present in the water supply system. Many pathogens that are capable of polluting water distribution systems originate from humans or animals. For this reason, conducting tests for the detection of coliform bacteria is essential to ensuring that the water is restored to the safest point possible. While testing for pathogens in general is extremely tedious, and expensive, the same does not hold true for the testing of coliform bacteria.