Coliforms were chosen as indicators of microbial contamination of water in the 1880s. Total Coliforms are considered an indicator of overall water quality and treatment efficiency.
There is no correlation between Total Coliform and human health; it is an indicator species group only.
When Total Coliform is detected in a water sample it is assumed that conditions within the water distribution system are favorable for bacterial growth, and pathogenic (disease causing) microorganisms may be present. Fecal Coliforms are a subgroup of the Total Coliform organisms.