South Saint Paul Water Hardness & Quality Report (2026)

South Saint Paul, Minnesota, in Dakota County — a Dakota County city directly south of St. Paul on the Mississippi River, historically one of the major cattle and meatpacking centers of the Upper Midwest (the South Saint Paul Stockyards were among the nation's largest) — receives its municipal water from the City of South Saint Paul or St. Paul Regional Water Services (SPRWS), which draws from the Mississippi River at the St. Paul intake or from local Dakota County groundwater wells, serving the south St. Paul corridor.

The hard 207 mg/L hardness and elevated TDS of 463.3 mg/L reflect the Mississippi River at St. Paul's carbonate-rich character. The Mississippi River at St. Paul-Dakota County drains the Twin Cities metropolitan basin — terrain underlain by the Ordovician Prairie du Chien Group (dolostone), Ordovician Jordan Sandstone, and the Devonian-Silurian carbonate platform of the central Upper Midwest. The St. Paul-Minneapolis reach of the Mississippi receives carbonate-loaded tributary inflow from the Minnesota River (glacial till-draining) and the St. Croix River (siliceous Cambrian sandstone — softer), mixing to produce the moderately hard to hard supply characteristic of the Twin Cities metropolitan corridor.

At 207 mg/L, South Saint Paul's water is hard — scale builds in kettles and appliances within weeks, dishwashers require rinse aid, and bathroom fixtures develop calcium deposits. Monthly descaling of heating appliances is practical. A water softener is recommended. The PFAS level of 5.9 ppt warrants a certified drinking water filter — 3M (Cottage Grove, MN — the Mississippi River corridor downstream from 3M's manufacturing complex, a primary PFAS manufacturing site) and the Minnesota-Mississippi PFAS industrial legacy are primary contributors to St. Paul area PFAS readings.