Hardness

A characteristic of water determined by the levels of calcium and magnesium. Water hardness is largely the result of geological formations of the water source. Public acceptance of hardness varies. Hardness of more than 300-500 mg/l as calcium carbonate is considered excessive for a public water supply and results in high soap consumption as well as objectional scale in heating vessels and pipes, and sometimes causes objectionable tastes in drinking water. Many consumers object to water harder than 150 mg/l, a moderate figure being 60-120 mg/l.