It used to be that if one wanted cups of water at the WDW QS, one had to wait in line.
I have also seen QS locations put cups of water out on the counter for anyone to take.
When WDW re-opens, and if the water fountains are closed. They might not do either of the above.
Maybe the QS locations will have a designated water cup area. Or maybe WDW will add something vaguely similar to Universal's butterbeer stands, except they offer water?
I've also seen a number of hotel lobbies offer free water, including the Universal hotels. WDW hotels have offered free towels on rainy days before. Maybe the WDW will offer more water that way. When you check into a WDW hotel, everyone in your party gets some water.
It is possible WDW will offer bottled water at lower prices than before. Maybe they will offer less premium water at a low price, and more premium water at higher prices?