Water Quality Division: Safe Drinking Water: Ground Water Rule

Short Description of the Ground Water Rule (GWR)

The U.S. Environmental Protection Agency (EPA) published the Ground Water Rule (GWR) in the Federal Register on November 08, 2006. The purpose of the rule is to provide for increased protection against microbial pathogens in public water systems that use ground water sources. The U.S. EPA is particularly concerned about ground water systems that are susceptible to fecal contamination since disease-causing pathogens may be found in fecal contamination.

The GWR will apply to public water systems that serve ground water. The rule also applies to any system that mixes surface and ground water if the ground water is added directly to the distribution system and provided to consumers without treatment.

Final Requirements

The targeted, risk-based strategy addresses risks through an approach that relies on four major components:

  • Periodic 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 when a system (that does not already treat drinking water to remove 99.99 percent (4-log) of viruses) identifies a positive sample during its Total Coliform Rule monitoring and 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;
  • Compliance monitoring to ensure that treatment technology installed to treat drinking water reliably achieves 99.99 percent (4-log) inactivation or removal of viruses.

Guidance Documents and Forms

Situations Requiring Public Notice Under the GWR

Public Notice Templates available below. Edit the highlighted sections according to the specific situation.

Public Water Systems (PWSs) must submit this signed Certificate of Public Notice Distribution and provide a copy of each public notice within ten (10) days of issuance. PWSs should consult with the ADEQ Rule Specialists (contact information below) for appropriate methods of public notice.

Tier 1 Public Notice (Immediate Notice, within 24 hours)

A system is notified of a fecal indicator-positive ground water source sample (either a triggered source water monitoring sample, one of its five additional samples required by a positive triggered source water monitoring sample, or an assessment source water monitoring sample) that is not invalidated by the state.

A system has a replacement source water sample that is fecal indicator-positive.

For these types of situations, CWSs must also place a Special Notice in the year's CCR and must add the fecal indicator-positive result to the regulated contaminant table in the CCR.

Tier 1 Public Notice Template - Fecal Indicator Positive (Word)

Tier 2 Public Notice (Notice as Soon as Practical, within 30 days)

A Ground Water System has a Treatment Technique (TT) Violation under the GWR. TT violations result from:

  • Failing to comply with or be on a compliance schedule for a state-approved corrective action plan within 120 days of being notified of a significant deficiency.
  • Failing to comply with or be on a compliance schedule for a state-approved corrective action plan within 120 days of being notified of a fecal indicator-positive source water sample.
  • Failing to maintain at least 4-log treatment of viruses for more than 4 hours.

Tier 2 Public Notice Template - Failure to Comply with Corrective Action Plan (Word)
Tier 2 Public Notice Template - Failure to Maintain 4 log Treatment (Word)

CWSs that have TT violations must also place information about the violation in the year's CCR.

Tier 3 Public Notice (Annual Notice or Consumer Confidence Report)

A Ground Water System fails to meet GWR Monitoring Requirements if the system:

  • Fails to conduct triggered source water monitoring within 24 hours of being notified of a total coliform-positive routine sample.
  • Fails to collect five additional samples after a fecal indicator-positive triggered source water sample (unless the state requires corrective action).
  • Fails to collect a replacement source water sample within 24 hours of being notified that a fecal indicator-positive sample has been invalidated by the state.
  • Fails to conduct or follow the requirements for assessment source water monitoring as directed by the state for existing or new sources (coming into service after November 30, 2009).

Tier 3 Public Notice Template - Failure to Collect Source Water Samples (Word)

A Ground Water System fails to meet Compliance Monitoring Requirements if the system:

  • Does not conduct triggered source water monitoring and fails to conduct monitoring to demonstrate compliance with 4-log treatment requirements.

Tier 3 Public Notice Template - Failure to Conduct Compliance Monitoring (Word)

CWSs that violate monitoring requirements must place information about the monitoring violation in the year's CCR.

Notify ADEQ

Laboratories and Public Water Systems may now notify ADEQ by e-mail of a Total Coliform Rule positive sample under the Ground Water Rule. Include the Public Water System number within the e-mail. Please note, results must still be submitted in hardcopy by fax or mail on approved ADEQ forms.

Donna Calderon, Drinking Water Monitoring and Protection - (602) 771-4641
Janell Goatson, Monitoring and Public Notice - (602) 771-4572

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