Tapcensus

Groundwater Rule (GWR) violations in Arizona

103 active public water systems in Arizona had a Groundwater Rule (GWR) violation in the past three years, 106 of them in the latest quarter of EPA's data. What Groundwater Rule (GWR) is and why it matters.

Health effects: Protects against enteric viruses, which can contaminate groundwater via cracked well casings, failing septic systems, or animal waste. Viruses persist longer in groundwater than in surface water. Hepatitis A and norovirus are the primary pathogens of concern.

Systems with a Groundwater Rule (GWR) violation

Latest quarter first, then largest first
SystemServesStatusRules violated, 3 yrUnresolved
Silver Creek Water Company
Oatman · Mohave County 		25 2 1
Cathedral Rock Estates Water Coop
Sedona · Yavapai County 		19 2 1
Lake Havasu City of
Lake Havasu City · Mohave County 		54,610 2 0
About this data

A system is counted once if any of its violations in the past three years involved Groundwater Rule (GWR), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Groundwater Rule (GWR) alone.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Arizona records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.