What are coliform bacteria?
Coliform bacteria are organisms that are present in the environment and in the feces of all warm-blooded animals and humans. Coliform bacteria will not likely cause illness. However, their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system. Most pathogens that can contaminate water supplies come from the feces of humans or animals. Testing drinking water for all possible pathogens is complex, time-consuming, and expensive. It is relatively easy and inexpensive to test for coliform bacteria. If coliform bacteria are found in a water sample, water system operators work to find the source of contamination and restore safe drinking water. There are three different groups of coliform bacteria; each has a different level of risk. Total coliform, fecal coliform, and E. coli Total coliform, fecal coliform, and E. coli are all indicators of drinking water quality. The total coliform group is a large collection of different kinds of bacte
Coliform bacteria include a large group of common bacteria. Some of these bacteria are harmful but many are harmless. They are used as an “indicator” to determine whether a pathway exists for dangerous bacteria to enter your water supply. Their presence does not guarantee that your water is unsafe to drink, but it does indicate that harmful bacteria could enter your water at any time. Coliform bacteria occur in about half of the private wells and springs in Pennsylvania.
