Total Coliform
Total coliform bacteria is a common form of bacteria that grows in soil and can be carried by insects. Water contaminated with total coliform bacteria, if consumed, can cause an upset stomach, diarrhea, and/or vomiting. However, it is more likely to affect children, the elderly, or anyone with a compromised immune system. The human body can have or build immunity to total coliform bacteria, so it is possible for a person to drink water contaminated with total coliform bacteria without getting sick. Therefore, a well may be contaminated without the homeowner knowing unless the water is tested in a laboratory.
If a well is positive for total coliform bacteria it may also have more harmful bacteria present. Therefore, it is important to property chlorinate the well and have it retested.