Desalination of ground water from a well

My ground well has salty water and can not be used for drinking. The water damages  clothes in washing ,the floor in cement or tiles or other concrete material changes color in contact with that water. Taps ,shower mixers ,all damaged by this water . This water is used by one religious community with more than 50 persons for all needs. Can you please  suggest me any treatments to let my well be useful. Regards Seff