Rosemount Water Hardness & Quality Report (2026)

The City of Rosemount, located in Dakota County, Minnesota, operates a municipal water system supplied entirely by groundwater wells. The utility provides drinking water to the city and surrounding service area, drawing from deep municipal groundwater wells that tap into the region's aquifer system. The city works closely with the Minnesota Department of Health to ensure regulatory compliance and safe drinking water delivery to all residents. Annual Consumer Confidence Reports detailing treatment processes and contaminant levels are published by the city each year.

Rosemount's water supply originates from the Minnesota River Valley aquifer system, which is underlain by Precambrian granite and gneiss bedrock overlain by glacial deposits and sedimentary formations. This geological setting is characteristic of southeastern Minnesota and produces naturally very hard water due to the dissolution of calcium and magnesium minerals from carbonate-rich formations. The groundwater hardness reaches 291 mg/L, reflecting the region's mineral-rich hydrogeology.

At the very hard classification (291 mg/L), scale buildup in water heaters, kettles, and plumbing fixtures is significant, reducing the efficiency of soaps and detergents. Appliances such as dishwashers and washing machines require more frequent maintenance and descaling. A water softener is strongly recommended for all households. Rosemount's water has a pH of 7.7, contains iron at an average of 0.53 mg/L and fluoride at 0.7 mg/L. In January 2026, the Minnesota Department of Health identified that Rosemount Well #8 exceeded regulatory standards for Gross (total) Alpha radiation on an annual average basis; the city maintains active monitoring to meet drinking water standards.