EPA Groundwater Rule
The groundwater source monitoring as required under the EPA Groundwater Rule, applies to all public water systems that use groundwater sources or purchase groundwater. The purpose of the rule is to protect the public from fecal-related bacterial and viral pathogens in public groundwater systems. E. coli is used as the indicator of fecal contamination.
If a groundwater source (well or spring) is found to be fecally contaminated, the public water supplier must take corrective action to assure that their consumers are adequately protected. The coliform monitoring required under this rule is different from the required coliform monitoring in the distribution system.