Total coliform bacteria are commonly found in the environment and are generally harmless. The total coliform test is considered an indicator, since the presence of bacteria in this group indicates a possibility, not a certainty, that disease causing bacteria may be present in the water.
When total coliforms are absent (labeled A on your report) there is a very low probability of disease causing organisms being present in your water.
When total coliforms are present (labeled P on your report) you should take a second (or confirmation) water sample for analysis. This will show whether bacteria were really in the water sample or if there was a sampling or lab error.
If samples show coliform bacteria, you should disinfect your well and/or your plumbing.
The presence of Escherichia coli (E. coli) bacteria indicates that the water may be contaminated with microorganisms that can cause disease which represent a serious health concern.
When E. coli are absent (labeled A or left blank on your report) there is a very low probability of disease causing organisms being present in your water. This is sometimes left blank because when total coliforms are absent, E. coli bacteria are also absent.
When E. coli are present (labeled P on your report) the water is not safe to drink. The source of contamination needs to be found and corrected. You should disinfect your well and/or your plumbing.