Drinking Water Requirements for States and Public Water Systems

Ground Water Rule

Rule Summary

EPA issued the Ground Water Rule (GWR) to improve drinking water quality and provide protection from disease-causing microorganisms. Water systems that have ground water sources may be susceptible to fecal contamination. In many cases, fecal contamination can contain disease causing pathogens. The purpose of the Ground Water Rule (GWR) is to reduce disease incidence associated with harmful microorganisms in drinking water.

The GWR applies to public water systems that use ground water as a source of drinking water. The rule also applies to any system that delivers surface and ground water to consumers where the ground water is added to the distribution system without treatment. The GWR was published in the Federal Register on November 8, 2006. 

Quick Reference Guides to Ground Water Rule (GWR)

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Rule History

The Ground Water Rule (GWR) was signed by the EPA Administrator Stephen L. Johnson on October 11, 2006. EPA published the GWR in the Federal Register on November 08, 2006.  The GWR provides protection against microbial pathogens in public water systems using ground water sources.

GWR Supporting Documents – The following documents have been developed to support the final rule-making.

Rule Making History

Related Federal Register Notices


The GWR establishes a risk-based approach to target ground water systems vulnerable to fecal contamination. Ground water systems that are at risk of fecal contamination must take corrective action. Corrective action reduces potential illness from exposure to microbial pathogens. The rule applies to public water systems that use ground water as a source of drinking water.

Final Requirements:
The GWR’s targeted, risk-based strategy addresses risks through an approach that relies on four major components:

  • Routine sanitary surveys of systems that require the evaluation of eight critical elements of a public water system and the identification of significant deficiencies (e.g., a well located near a leaking septic system);
  • Triggered source water monitoring for a system that (not treating drinking water to remove 99.99 percent (4-log) of viruses) identifies a positive sample during regular Total Coliform monitoring or assessment monitoring (at the option of the state) targeted at high-risk systems;
  • Corrective action is required for any system with a significant deficiency or source water fecal contamination; and
  • Compliance monitoring to ensure that treatment technology installed to treat drinking water reliably achieves 99.99 percent (4-log) inactivation or removal of viruses.

Compliance Help

For Water System Owners and Operators

For Primacy Agencies