What role does salt have in the softening process?

Salt comes in many forms (block, tablet, granular) and is loaded into the water softener in order to mix with a reservoir of water and dissolve into brine solution.

The brine solution is then used in the regeneration process, whereby it chemically removes the calcium and magnesium ions captured by the resin beads for exchange of a sodium ion. The solution is then expelled to the drain. At this point, the resin beads have been recharged and are ready to capture more calcium magnesium.