Arizona Well Water
Last reviewed October 29, 2026
Overview
Private wells supply water to many Arizona households. Because they are generally not regulated like public systems under the federal Safe Drinking Water Act, testing and wellhead protection are the owner’s responsibility.
Hydrogeology & what it means
Arizona relies on alluvial basin-fill aquifers across its desert basins. The documented regional concerns below indicate what is worth testing for — not what any individual well contains.
Documented regional concerns
- Naturally occurring arsenic in parts of the state — odorless and tasteless, so only testing reveals it.
- Naturally occurring fluoride above recommended levels in some groundwater.
- Naturally occurring uranium in some aquifers.
- High total dissolved solids/salinity in some aquifers.
- Hard water from carbonate (limestone/dolomite) aquifers.
These are documented possibilities, not a reading of your well
Frequently asked questions
What should well owners in Arizona test for?
A practical panel for Arizona private wells includes Total coliform bacteria, Nitrate (as N), pH, Arsenic, Fluoride, Uranium, Total dissolved solids, Total hardness. Test bacteria and nitrate at least annually and use a state-certified laboratory; confirm local recommendations with your state health department and University of Arizona Cooperative Extension.
Are private wells regulated in Arizona?
Private wells are generally not covered by the federal Safe Drinking Water Act, though Arizona or local rules may apply to construction, permitting, or testing. Public-system limits such as EPA MCLs are useful reference points, not automatic legal limits for your well.