Coon Rapids Water Hardness & Quality Report (2026)

Coon Rapids, Minnesota, in Anoka County — one of the Twin Cities' largest northern suburbs at the Coon Rapids Dam on the Mississippi River — draws its municipal water supply through the City of Coon Rapids Water Division, receiving a blend of Minneapolis Water Works treated Mississippi River water and local Anoka County groundwater from the Anoka Sand Plain Aquifer (Quaternary glaciofluvial sand and gravel). Water hardness in the eastern Coon Rapids zone measures 190 mg/L — classified as hard, notably harder than the west Coon Rapids–West Coon Rapids area (137.5 mg/L on the same municipal system).

The harder 190 mg/L in the east Coon Rapids distribution zone compared to west Coon Rapids (137.5 mg/L) reflects the different supply blending within the Coon Rapids system. The Anoka Sand Plain Aquifer beneath eastern Coon Rapids has a higher proportion of local well supply relative to the Minneapolis Water Works Mississippi surface water. The Anoka Sand Plain — a major glaciofluvial outwash plain deposited by the retreating Laurentide Ice Sheet from the calcareous Des Moines Lobe glacier (which carried calcareous till from the Iowa–Minnesota Cretaceous calcareous shale terrain) — has moderately high calcareous content. A higher proportion of this calcareous local groundwater in the east Coon Rapids distribution zone produces the harder 190 mg/L reading.

At 190 mg/L, Coon Rapids residents in the eastern distribution zone face regular hard water challenges. Scale deposits form on faucet aerators, showerheads, and appliances within weeks — monthly descaling with citric acid solution is standard maintenance. City of Coon Rapids Water Division consistently delivers water meeting all Minnesota MDH and EPA Safe Drinking Water Act requirements.