What are coliform bacteria?
Coliform bacteria make up a large group of bacteria that are found in soils, on plants, and in surface water. Certain coliform bacteria live in the intestines of humans and animals.
Coliforms are not harmful themselves, but when present in drinking water, disease-causing microorganisms such as bacteria, viruses, and parasites may have gotten into the water supply by the same route as the coliforms. The Maine Health and Environmental Testing Laboratory (HETL) tests for coliforms as an indicator for possible contamination.