Water Softener is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water is more compatible with soap and extends the lifetime of plumbing. Water softening is usually achieved using lime softening or ion-exchange resins.

Conventional water-softening appliances intended for household use depend on an ion-exchange resin in which “hardness ions” – mainly Ca and Mg – are exchanged for sodium ions. As described by NSF/ANSI Standard 44, ion-exchange devices reduce the hardness by replacing magnesium and calcium (Mg’andCa’) with sodium or potassium ions (No* and K).”lon exchange resins, in the form of beads, are a functional component of domestic water softening units.