The most commonly tested fecal bacteria indicators are total coliforms, fecal coliforms, and E. coli (Escherichia coli) are composed of a number of species of bacteria that share common characteristics such as shape, habitat, or behavior; E. coli is a single species in the fecal coliform group. Total coliforms are a group of bacteria that are widespread in nature. All members of the total coliform group can occur in human feces, but some can also be present in animal manure, soil, and submerged wood and in other places outside the human body. For drinking water, total coliforms are still the standard test because their presence indicates contamination of a water supply by an outside source.
Fecal coliforms, a subset of total coliform bacteria, are more fecal-specific in origin. Fecal coliforms are still being used in many states as the indicator bacteria. E. coli is a species of fecal coliform bacteria that is specific to fecal material from humans and other warm-blooded animals. EPA recommends E. coli as the best indicator of health risk from water contact in recreational waters; some states have changed their water quality standards and are monitoring accordingly.
Testing for bacteria's is mandatory for all new wells drilled in North Carolina, and suggested for all spring fed residential supply sources every 6 months.
