Marana Water Hardness & Quality Report (2026)

The Town of Marana Water Department serves approximately 60,000 residents across Marana and surrounding areas in Pima County, Arizona, including service systems such as Picture Rocks, Palo Verde, Gladden Farms, Hartman Vistas, and Marana Regional Airport. Water is drawn exclusively from local groundwater wells tapping into the Avra Valley and Upper Santa Cruz Basin aquifers. There are no surface water treatment plants; raw groundwater is pumped from more than 20 wells, with basic treatment involving chlorination, fluoridation, and occasional blending from multiple wells to manage quality variations across service areas.

The Avra Valley groundwater basin, bounded by the Silver Bell Mountains to the west and the Tucson Mountains to the east, forms part of the larger Santa Cruz River regional aquifer system. Water chemistry is shaped by recharge from ephemeral streams infiltrating through alluvial fans composed of limestone and volcanic rock fragments from the surrounding Santa Catalina and Tortolita Mountains. The aquifer's carbonate-rich alluvial deposits and fractured bedrock dissolve calcium and magnesium during groundwater percolation, contributing to a hard supply with elevated mineral content that influences taste, scaling potential, and treatment needs.

Very hard water promotes significant scale buildup in pipes, water heaters, dishwashers, and washing machines — water heaters may fail 30–50% sooner without mitigation. Fixtures with heating elements and narrow passages are most affected. Regular vinegar descaling, low-flow aerators, and magnetic descalers help, but a whole-house water softener is strongly recommended to prevent spotting on dishes and glassware, prolong appliance life, and improve soap efficiency by reducing detergent use by up to 50%. Water quality meets all EPA standards; pH is typically 7.5–8.2, with no PFAS detections above lab limits and low arsenic after blending.