A new rule issued by the Environmental Protection Agency last fall targets utilities that provide water from underground sources and requires greater vigilance for potential contamination by disease-causing microorganisms.

The risk-targeting strategy in the rules provides for:

  • Regular sanitary surveys of public water systems to look for significant deficiencies in key operational areas.


  • Triggered source-water monitoring when a system that does not sufficiently disinfect drinking water identifies a positive sample during its regular monitoring to comply with existing rules.


  • Implementation of corrective actions by ground water systems with a significant deficiency or evidence of source water fecal contamination


  • Compliance monitoring for systems that are sufficiently treating drinking water to ensure effective removal of pathogens.

    Contaminants in question are pathogenic viruses - such as rotavirus, echoviruses, noroviruses - and pathogenic bacteria, including E. coli, salmonella, and shigella. Utilities will be required to look for and correct deficiencies in their operations to prevent contamination from these pathogens.

    The EPA says fecal contamination can reach ground water sources, including drinking water wells, from failed septic systems, leaking sewer lines, and by passing through the soil and large cracks in the ground. Fecal contamination from the surface may also get into a drinking-water well along its casing or through cracks if the well is not properly constructed, protected or maintained.

    A ground water system is subject to triggered source-water monitoring if its treatment methods don’t already remove 99.99 percent of viruses. Systems must begin to comply with the new requirements by Dec. 1, 2009.

    For more information, visit www.epa.gov/safewater/disinfection/gwr.