Farmington Water Hardness & Quality Report (2026)

Farmington, Minnesota, in Dakota County in the southern Twin Cities metropolitan area — a fast-growing Dakota County community along the Vermillion River corridor that has expanded rapidly as outer-ring suburban development expanded south of the Twin Cities — receives its municipal water from the City of Farmington Water Utility, which draws from groundwater wells in the Vermillion River watershed or from regional Dakota County supply interconnections. Farmington's growing population has driven expansion of its municipal water production capacity in the Vermillion River basin.

The moderately hard 118 mg/L hardness and TDS of 205.4 mg/L reflect the southern Dakota County groundwater and surface water supply's carbonate terrain character. The Vermillion River drainage in Dakota County overlies the Ordovician Prairie du Chien Dolomite and Jordan Sandstone — two prominent carbonate and calcareous formations in the Twin Cities metro bedrock sequence — supplemented by Pleistocene glacial till with carbonate-rich grain composition from limestone-bearing Laurentide Ice Sheet material. This combination of dolomite bedrock and calcareous glacial till in the south metro zone produces a moderately hard groundwater and surface water supply.

At 118 mg/L, Farmington's water is moderately hard — manageable for everyday household use in this growing Dakota County community. Scale builds gradually in kettles and appliances over months, the dishwasher benefits from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling of heating appliances is the standard schedule. The PFAS level of 3.9 ppt is among the better readings in the Twin Cities southern suburbs — Farmington's rural-to-suburban character in southern Dakota County, with limited industrial and military PFAS sources in the Vermillion River watershed, produces a relatively clean PFAS profile for the Minneapolis metro.