State Well Water Guide
Arizona Private Well Water Guide
Arizona's private well users — primarily in rural areas outside the Phoenix and Tucson metro served areas — face some of the most challenging well water conditions in the nation. The state's arid geology concentrates naturally occurring contaminants including arsenic, uranium, fluoride, and chromium-6 in groundwater. Aquifer overdraft is also a serious concern, with many rural Arizona wells experiencing declining water levels. The Arizona Department of Environmental Quality (ADEQ) regulates public water systems; private domestic wells (fewer than 5 service connections) are minimally regulated.
Testing Guidance
ADEQ and University of Arizona Extension recommend annual testing for bacteria and nitrates as a minimum. Given Arizona's geology, arsenic testing is strongly recommended for all wells — Arizona has documented some of the highest naturally occurring arsenic in groundwater in the United States. Testing for uranium, fluoride, and chromium-6 is advised based on location. All new wells and wells that haven't been tested in 3+ years should receive a comprehensive panel including heavy metals, radiologicals, and VOCs.
What to Test For in Arizona
Total coliform bacteria and E. coli — annual minimum for all wells
Arsenic — all Arizona wells; state ranks among highest naturally occurring arsenic in the nation
Uranium — granitic geology areas; southeastern Arizona, Prescott region
Fluoride — many rural Arizona aquifers have naturally elevated fluoride; some areas exceed the EPA MCL of 4 mg/L
Chromium-6 — Prescott Valley area, Gila River basin, and near industrial sites
Nitrates — wells near agricultural areas, feedlots, or septic systems
Perchlorate — Phoenix metro area, Litchfield Park, and areas with aerospace/defense industry history
Total dissolved solids and hardness — Arizona groundwater is typically very hard (200–600+ mg/L)
PFAS — near Luke Air Force Base, Davis-Monthan, Fort Huachuca, and other military installations
Iron and manganese — some rural areas of central and eastern Arizona
Common Contamination Risks in Arizona
Arsenic — Arizona consistently reports among the highest naturally occurring arsenic concentrations in U.S. groundwater; volcanic and sedimentary geology releases arsenic across much of the state
Uranium from granitic and sedimentary rock — southeastern Arizona and the Prescott region have documented uranium in groundwater from naturally occurring ore deposits
Fluoride from volcanic geology — naturally elevated fluoride occurs in many areas; the Tucson Basin, parts of Yavapai County, and eastern Arizona have documented levels at or above the EPA MCL
Perchlorate in the Phoenix area — legacy aerospace and defense industry contamination has left perchlorate plumes affecting groundwater in parts of the West Valley
Aquifer depletion — many rural Arizona aquifers are being pumped faster than natural recharge, causing water quality changes (increased mineral concentration, arsenic mobilization) as water tables drop
PFAS from military and aviation — Luke AFB, Davis-Monthan, Fort Huachuca, and commercial airports have documented PFAS releases affecting surrounding groundwater
Extreme water hardness — Arizona groundwater is among the hardest in the nation; scale buildup in pipes and appliances is nearly universal without treatment
Contaminant Guides Relevant to AZ Wells
Find a Certified Lab in Arizona
Use the Arizona state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
AZ Certified Lab Directory ↗Arizona Well Water FAQs
Related Pages
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Quick Reference
State program
AZ Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
AZ Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides