What are coliform?
Coliform bacteria are indicator organisms which are used in water microbiological analysis. Coliforms are a group of bacteria which are readily found in soil, decaying vegetation, animal feces, and raw surface water. They are not normally present in deep groundwater and treated surface water. These indicator organisms may be accompanied by pathogens (i.e., disease-causing organisms), but do not normally cause disease in healthy individuals. However, individuals with compromised immune systems should be considered at risk. Coliforms, rather than the actual pathogens, are used to assess water quality because their detection is more reliable. Pathogens appear in smaller numbers than coliforms, so are less likely to be isolated. Drinking water found to contain coliforms is considered biologically contaminated.
