What should a water system operator do if E. coli is found in their bacteriological sample?
A. First and foremost, every user on the water system must be notified that the water is contaminated with E. coli, and that they should immediately begin using bottled water for all their drinking and culinary needs, or vigorously boil their water for a minimum of one (1) minute before using for drinking or culinary purposes. (Due to other water quality issues, using bottled water may be the preferred interim measure put into effect until the water is deemed to be free of E. coli. For example, if a water system has nitrate levels near the Maximum Contaminant Level (MCL), boiling the water will cause some water to be released as steam while the nitrate stays in the liquid that is left behind. This will actually increase the nitrate concentration. Therefore, boiling water with high levels of nitrate could cause it to exceed the MCL (45 mg/L), making it unsuitable for human consumption.) The water system operator needs to work closely with Environmental Health to investigate and resolve
