Water can be hard or soft depending on the amount of dissolved minerals like calcium and magnesium. Hard water causes scale buildup and reduces cleaning product efficiency. There are several methods to remove hardness from water including lime-soda softening, cation exchange, distillation, reverse osmosis, and ion exchange. Lime-soda softening uses lime and soda ash to precipitate minerals out of solution. Cation exchange uses zeolites to replace calcium and magnesium ions with sodium ions.