Northfield Water Hardness & Quality Report (2026)

Northfield, Minnesota, in Rice County — a classic small Minnesota college town on the Cannon River, home of both Carleton College (a highly selective liberal arts institution) and St. Olaf College (a Lutheran liberal arts college), famous for the Defeat of Jesse James Days commemorating the 1876 failed bank robbery — receives its municipal water from Northfield Public Utilities, which draws from the Cannon River surface water intake or from local groundwater wells in the Rice County aquifer.

The moderately hard 155.5 mg/L hardness and TDS of 303.4 mg/L reflect the Cannon River watershed's southern Minnesota glacial carbonate geology. The Cannon River drains the Southern Minnesota Till Plain (the Des Moines Lobe glacial till — calcareous limestone-rich Pleistocene deposits) over the Ordovician Oneota Dolomite and Prairie du Chien Group (dolostone and chert), the Cambrian Jordan Sandstone, and the Cambrian St. Lawrence Formation (calcareous dolomite). These southern Minnesota carbonate formations produce moderately hard water throughout the Cannon River valley, consistent with the broader Minnesota Twin Cities south-metro aquifer character.

At 155.5 mg/L, Northfield's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and bathroom fixtures develop calcium deposits. Quarterly descaling is appropriate. The PFAS level of 4.7 ppt warrants a certified drinking water filter — the Rice County agricultural corridor, the Minnesota National Guard training areas in the southern Minnesota region, and the Cannon River watershed's agricultural runoff all contribute to Northfield's PFAS background.