It's still a valid question depending on WHY he is asking.
I'm currently water loading/sodium for a few days and then dehydrating in order to weigh-in in a lower weight class. After that I'll rehydrate with Pedialyte and glycine immediately after weigh-ins followed by water and a crap load of food the rest of the day.
I would just drink something with electrolytes. Not salt water. Hence the Pedialyte.