A water sample is "present for total coliform" or "total coliform positive" if coliform bacteria are found in the sample. Generally, coliforms are bacteria that are not harmful and are naturally present in the environment. They are used as an indicator that other, potentially harmful, fecal bacteria (indicated by the E. coli species) could be present. If any routine or repeat sample is total coliform positive or present, the system (i.e., the lab) must further analyze that sample to determine if E. coli are present. E. coli is a more specific indicator of fecal contamination and is a potentially more harmful pathogen than other bacteria typically found in the total coliform group. The presence of coliform bacteria in tap water suggests that there could be a problem with existing equipment or treatment systems, contamination of the source water, or a breach in the distribution system that could introduce E. coli contamination. *Source Environmental Protection Agency (EPA)
When a water system receives a total coliform positive or total coliform present sample result, within 24 hours, the owner or operator of the system must collect a set of repeat total coliform samples in the distribution system; all groundwater sources must be sampled for E. coli. The purpose of the repeat samples are to confirm the presence of coliform bacteria in the system and to determine if the groundwater source or distribution system is contaminated with E.coli.
If repeat samples are negative, ROUTINE sampling will be conducted the following month.