Apple Valley Water Hardness & Quality Report (2026)

The City of Apple Valley Public Works Department operates the drinking water system in Apple Valley, Dakota County, Minnesota, serving a population of approximately 55,000. Supply comes from 19 wells — 14 active and 5 standby — tapping the Prairie du Chien-Jordan and Jordan aquifers as primary sources, with the Mt. Simon aquifer serving as emergency backup. Water is treated at a facility capable of processing up to 18 million gallons daily, with treatment including chlorination at 0.7–1.2 ppm residual and fluoridation at 0.6–0.9 ppm before distribution.

The supply originates from groundwater aquifers of the Minnesota River Valley. Key formations include the Jordan Sandstone (Ordovician) and the underlying Prairie du Chien Group — limestone and dolomite of Cambrian-Ordovician age. These carbonate-rich layers dissolve minerals into the water through prolonged groundwater flow via wells ranging 487 to 1,127 feet deep, yielding elevated calcium and magnesium concentrations. The karst geology of these aquifers is the primary reason for the very hard supply, with mineralisation promoted by extended contact between groundwater and carbonate rock.

At 411 mg/L, Apple Valley's water is very hard, causing significant scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Kettles and fixtures show white mineral deposits quickly. A water softener is strongly recommended for households to prevent spotting on glassware and dry skin and hair. Regular descaling and vinegar rinses help with ongoing maintenance. The water maintains pH 7.2–7.5; iron traces, manganese at 0.060–0.090 ppm, and nitrates at 0.13–0.16 ppm are present but below EPA MCLs, with no specific PFAS or lead/copper violations noted in available data.