Water with elevated dissolved calcium and magnesium minerals.
Most Utah well water is moderately to extremely hard because groundwater dissolves calcium carbonate from limestone and dolomite formations. Hard water leaves scale on fixtures, shortens water-heater life, and reduces soap effectiveness. Hardness is reported in grains per gallon (gpg) or mg/L; anything over 7 gpg is considered hard. Treatment is typically a whole-house ion-exchange softener.