hardness

Hard water is defined by the presence of dissolved minerals, primarily calcium and magnesium salts. These minerals can cause issues such as scale buildup in pipes and tanks, and they interfere with the lathering action of soap. While hard water does not pose a health risk, the economic and practical problems it causes make it undesirable.123

Water softening is the process used to remove these hardness-causing minerals. Common methods include chemical treatment, such as the lime-soda process, or ion exchange, where water passes through a resin that exchanges sodium ions for calcium and magnesium ions. Home water softeners typically utilize the ion exchange method.12