Hardness in drinking water is caused by 2 nontoxic chemicals (usually called minerals), calcium and magnesium, both of which are widely distributed in common minerals of rocks and soils. If calcium and/or magnesium is present in your water in substantial amounts, the water is said to be "hard" because making a lather or suds for washing is hard (difficult) to do. Water containing little calcium or magnesium is called "soft" water.
River Falls water is not considered hard water. Hardness of waters in contact with limestone commonly exceeds 200 mg/L. In waters from gypsiferous formations, a hardness of 1,000 mg/L is not uncommon. The water hardness in River Falls is 16 grains per gallon or 272 mg/L.