There can be coliform bacteria in well water when the well is defective. Drinking water should not contain any presence of coliform bacteria for safety reasons, explains the Vermont Department of Health. If coliform bacteria is detected in the well water, then remediation steps are necessary to resolve the problem.
People with wells should have their water tested on a regular basis to see if it is safe for use. In New York, the recommendation is that wells be tested at least annually, according to the New York Department of Health. If water is found to be contaminated with coliform bacteria, then the well should be inspected for signs of defects. Some well problems that can cause water contamination are well caps or casings that are damaged in some way. Once the well is fixed, the water should be retested.
Coliform bacteria can be found in the fecal matter of animals and humans. It is also present in soil. When these bacteria are in the water supply, they can indicate that water-borne disease may also be present, states the Vermont Department of Health.