Hardness in Household Water
Hard water contains high levels of calcium and magnesium ions. These ions, among others, are naturally dissolved into groundwater as it comes in contact with soluble limestone and other rocks and minerals. While consuming hard water does not present a health risk, it may cause aesthetic or nuisance problems such as bitter taste or mineral deposits (scale) on dishes, utensils, and plumbing fixtures. Hard water can also reduce the efficiency and life span of water heaters.