Tapcensus

Gross Alpha, Excl. Radon and U violations in Arizona

15 active public water systems in Arizona had a Gross Alpha, Excl. Radon and U violation in the past three years, 1 of them in the latest quarter of EPA's data. What Gross Alpha, Excl. Radon and U is and why it matters.

Health effects: Alpha-emitting radionuclides accumulate in bone and soft tissue, delivering sustained internal radiation doses that increase lifetime cancer risk. There is no established safe threshold for ionizing radiation. Individual contributors such as radium-226 and polonium-210 have their own MCLs; gross alpha serves as a cost-effective screening tool that triggers more specific radionuclide analysis when exceeded.

Systems with a Gross Alpha, Excl. Radon and U violation

Latest quarter first, then largest first
SystemServesStatusRules violated, 3 yrUnresolved
Scua Bylas
Bylas · County 		3,160 12 3
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
Scua Upper Seven Mile
County 		8,478 12 3
Arizona Village
County 		3,211 10 2
Wellton Town of
Wellton · Yuma County 		3,000 10 1
Kerwo Intertie
Gu Vo, Pia Oik, Menegers Dam · County 		441 1 0
Shangri la Ranch
New River · Maricopa County 		345 6 2
Cocopah West
County 		325 2 0
Cocopah East
County 		280 3 0
Sonoita Valley (south) Water Company
Sonoita · Santa Cruz County 		172 4 2
About this data

A system is counted once if any of its violations in the past three years involved Gross Alpha, Excl. Radon and U, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Gross Alpha, Excl. Radon and U 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.