Tapcensus

Radium-226 violations in Arizona

7 active public water systems in Arizona had a Radium-226 violation in the past three years, 1 of them in the latest quarter of EPA's data. What Radium-226 is and why it matters.

Health effects: Radium-226 accumulates in bone tissue and delivers a sustained alpha radiation dose internally. Long-term exposure increases risk of bone cancer, and historic occupational data from radium dial painters established the carcinogenic mechanism. Children absorb more radium due to active bone growth, making them most vulnerable to skeletal radiation effects.

Systems with a Radium-226 violation

Latest quarter first, then largest first
SystemServesStatusRules violated, 3 yrUnresolved
Ponderosa Park Dwid
Prescott · Yavapai County 		602 5 1
Tucson City of
Tucson · Pima County 		732,906 3 0
GW Santa Cruz Water CO
Maricopa · Pinal County 		84,000 7 0
Bullhead City Mohave
Bullhead City · Mohave County 		36,330 13 1
Lago del Oro Water Company
Catalina · Pinal County 		18,132 2 0
City of Show Low
Show Low · Navajo County 		17,139 2 0
Epcor North East Agua Fria
Phoenix · Maricopa County 		14,723 2 0
About this data

A system is counted once if any of its violations in the past three years involved Radium-226, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Radium-226 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.