Well Drillers in Pinal County, AZ

Well Drillers in Pinal County, Arizona

Three licensed well drilling contractors serve Pinal County, one of Arizona’s fastest-growing counties. Pinal County is caught between two major metro areas and faces some of the most challenging groundwater conditions in the state — high arsenic, declining water tables, and a regulatory framework built for a transitional agricultural-to-urban county.

The Pinal Active Management Area

Most of Pinal County falls within the Pinal Active Management Area (Pinal AMA), which has a fundamentally different regulatory philosophy than the Phoenix or Tucson AMAs. Rather than targeting safe yield, the Pinal AMA was established with the recognition that it would experience substantial groundwater mining as it transitions from agricultural to urban uses.

Large housing developments in the Pinal AMA must demonstrate water adequacy — a 100-year supply — which has driven significant investment in Colorado River water rights transfers, water banking, and reclaimed water infrastructure. For individual domestic wells, the key requirements are:

Notice of Intent to Drill filed with ADWR
Well registration and completion report upon completion
General prohibition on new non-exempt irrigation wells (1/2 acre or more of irrigation)

Arsenic Alert: Pinal County

Pinal County deserves special mention for arsenic: the county has some of the highest naturally occurring arsenic concentrations in Arizona. Portions of the county regularly show arsenic above 50 µg/L — five times the EPA Maximum Contaminant Level of 10 µg/L. Any new well in Pinal County should be tested for arsenic before the water is used for drinking or cooking, and treatment (typically reverse osmosis) should be installed if results exceed 10 µg/L.

Arsenic in Pinal County originates from geothermal activity, volcanic rock weathering, and the dissolution of arsenic-bearing minerals in the alluvial sediments.

Drilling Depths and Conditions

Apache Junction area: 300–700 feet for residential wells; alluvial basin sediments at the eastern edge of the Salt River Valley
Marana area: 150–400 feet in the Avra Valley alluvial deposits; more predictable than the east county
Central Pinal (Eloy, Coolidge, Casa Grande): 300–600 feet; historically agricultural and subject to significant existing cone-of-depression effects from past irrigation pumping