Grand Forks Water Hardness & Quality Report (2026)

Grand Forks, North Dakota, the Grand Forks County seat on the Red River of the North at the North Dakota–Minnesota border — a major regional hub city, home of the University of North Dakota (the state's flagship university), and one of the key agricultural processing and military (Grand Forks AFB, Minuteman missile wing) cities in the northern Great Plains — draws its municipal water supply from the Red River of the North via the City of Grand Forks Water Treatment Plant. Water hardness in Grand Forks measures 119.5 mg/L — classified as moderately hard.

Grand Forks' moderate hardness reflects the Red River Valley's Lake Agassiz calcareous lakebed geology. The Red River of the North drains the floor of Glacial Lake Agassiz — the enormous post-Wisconsin glacial lake that covered the entire Red River Valley of the North, Minnesota, and Manitoba. The Lake Agassiz lakebed sediments (calcareous clay and silt from glacial rock flour from the calcareous Precambrian Canadian Shield limestone terrain) and the calcareous Prairie Pothole glacial till of the Minnesota–North Dakota border zone contribute moderate dissolved calcium to the Red River. The flat Red River Valley has minimal topographic relief, producing slow drainage that allows moderate calcareous equilibration, producing the moderate 119.5 mg/L.

At 119.5 mg/L, Grand Forks residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. City of Grand Forks Water Treatment Plant consistently delivers water meeting all North Dakota DOH and EPA Safe Drinking Water Act requirements.