Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment.

A water softener is a fairly simple appliance that is stocked with salt. In water softening process the water supply passes through the water softener over resin beds, rows of resin beads perform an ion-exchange. The resin beads chemically attract the unwanted 'hard' mineral ions and exchange them with sodium ions.