Groundwater Contractors in Pima County, AZ

Groundwater Contractors in Pima County, Arizona

Pima County encompasses one of the driest large urban areas in North America. Tucson, the county seat, receives just 12 inches of annual rainfall yet supports over a million residents — a feat made possible by a combination of Colorado River water delivered by the Central Arizona Project (CAP), reclaimed water, and groundwater. For the rural and semi-rural areas of Pima County beyond the Tucson Water service boundary, private wells remain the only water source.

Groundwater in the Tucson Active Management Area

Pima County lies within the Tucson Active Management Area (Tucson AMA), established under the 1980 Groundwater Management Act. The Tucson AMA has achieved notable success in reducing per-capita groundwater dependence: the City of Tucson now meets roughly 80% of its water demand with CAP surface water, recharging much of it underground through the Clearwater Renewable Resources Facility and other recharge sites.

Despite this progress, the Tucson basin aquifer remains stressed in many areas from decades of past over-pumping. Water tables in the central Tucson basin have historically dropped by 100–200 feet from pre-development levels, though artificial recharge has partially recovered some areas.

Aquifer System Overview

The Tucson basin is a structural basin bounded by the Rincon, Santa Catalina, Tucson, and Sierrita mountain ranges. The basin fill consists of:

Shallow alluvial zone (0–100 feet): Near arroyos and the Santa Cruz River corridor; generally not used for domestic supply due to contamination vulnerability
Main basin-fill aquifer (100–500 feet): Primary residential well target zone; sand and gravel with interbedded clays
Deep consolidated sediments (500–1,000+ feet): Lower yield but excellent water quality in many areas; used by municipal and agricultural producers

Typical residential well depths in Pima County range from 200 to 600 feet in the Tucson basin; wells in outlying areas (Avra Valley, Altar Valley, or near Benson) may run shallower or deeper depending on local geology.

Sub-Areas Within Pima County

Avra Valley (west of Tucson): A separate sub-basin used heavily for recharge storage by Tucson Water. Domestic wells in this area are generally 200–400 feet deep.
Altar Valley (south of Tucson): Ranching country with modest groundwater resources and some water quality concerns.
Benson area (southeast corner): Tectonically complex terrain at the northwest edge of Cochise County; well depths and yields are more variable.

Water Quality in Pima County

Hardness: Moderate to very hard, 200–450 mg/L across most of the county. Water softeners are common.
PFAS: Davis-Monthan Air Force Base in southeast Tucson has documented PFAS groundwater contamination. ADEQ tracks this plume. If your well is within a mile of the base perimeter, testing is essential.
TCE and chlorinated solvents: Tucson is home to one of Arizona’s largest Superfund sites (the Tucson International Airport Area Superfund). Multiple TCE plumes exist in the southeastern Tucson basin. Tucson Water provides alternative water supplies to affected neighborhoods.
Arsenic: Present at low to moderate levels in some basins. Test any new well.
TDS: Generally 400–900 mg/L; palatable in most areas but reverse osmosis is popular for drinking water quality.

All Contractors in Pima County

Well Drillers

BJ Drilling Company Inc — Tucson — (520) 586-3282 — bjdrilling.com
Western Water Wells LLC — Tucson — (520) 308-4047 — westernwells.com
Farwest Pump Company — Tucson — (520) 293-9778 — farwestwell.com
Geomechanics Southwest Inc — Tucson — (520) 889-7787 — gsidrilling.com
Reliant Well Drilling and Pump Corp — Tucson — (520) 293-9778 — reliantpump.services
Altar Drilling Inc — Tucson — (520) 882-0384
Mike’s Drilling, LLC — Tucson — (520) 399-2781 — mikesdrillingaz.com
Ironwood Well Service — Tucson — (520) 261-4516 — ironwoodwell.com
Titan Drilling — Benson — (520) 586-2616