Water softening is the process of removal of divalent cations from the water. They could be regenerated by flowing concentrated NaCl solution through them to release CaCl2 and MgCl2. However, they are seldom used for water softening.

Later on, ion exchange resins were developed that are of higher capacity and efficacy than zeolites. They have more affinity for magnesium and calcium ions than sodium ions. Therefore, it is necessary to force accumulated hardness ions off the resin beads with a solution of concentrated sodium chloride brine. The resins have many applications in commercial, residential, and industrial areas for water softening.