Where do you hear this stuff? Sometimes the wells right by the sea can get slightly salty in an extended dry season and hotel owners have to scramble for water for the guests but that is limited to a couple of places, and may not happen at all. Our showers and laundry are not salty, ever.
Those who spend much time living on boats can tell you- salt water washes your clothes OK. You can also tie them to the anchor line overnite to get that wave agitation action. Turns your clothes into rags.