A water softener device uses ion exchange to reduce the hardness by replacing magnesium and calcium (Mg2+ and Ca2+) with sodium or potassium ions (Na+ and K+). Ion exchange resins are organic polymers containing anionic functional groups to which the di-cations (Ca++) bind more strongly than mono-cations (Na+). Inorganic materials called zeolites also exhibit ion-exchange properties. These materials are used in some dish machine detergents. Regeneration of ion exchange resins takes place when most of the Na+ (or K ) ions have been replaced by calcium or magnesium ions, the resin must be refreshed by purging the Ca2+ and Mg2+ ions using a solution of sodium chloride or potassium chloride. The waste waters washed from the ion exchange column containing the unwanted calcium and magnesium salts are typically discharged to a sewer system.