Marshfield Water Hardness & Quality Report (2026)

Marshfield, Wisconsin, in Wood County — a Wood County city adjacent to Wisconsin Rapids in central Wisconsin, home of the Marshfield Clinic Health System (one of the largest integrated medical groups in the US) — receives its municipal water from the City of Marshfield Water Division, drawing from deep municipal wells accessing the Cambrian Jordan Sandstone and Ordovician Prairie du Chien Dolomite aquifer beneath Wood County.

The hard 185 mg/L hardness and high TDS of 523.9 mg/L reflect the deep carbonate aquifer character of central Wisconsin. The Ordovician Prairie du Chien Dolomite Group (thick dolomite platform underlying most of the Driftless-adjacent central Wisconsin) and the underlying Cambrian Trempealeau Formation (calcareous dolomitic sandstone) provide the primary aquifer for most central Wisconsin municipalities. The long residence time of the groundwater in the carbonate dolomite produces the hard water characteristic of the Marshfield-Wood County supply.

At 185 mg/L, Marshfield's water is moderately hard — scale builds rapidly in appliances and plumbing, particularly in water heaters and coffee makers. A water softener is recommended. The PFAS level of 5.1 ppt warrants a certified drinking water filter — the Marshfield Clinic central Wisconsin medical-industrial complex, the Wood County manufacturing corridor, and the central Wisconsin PFAS background (from agricultural applications and foam use) contribute to Marshfield's readings.