I am water picky, and I agree cups at the cs were just fine except the qs in China, they had prefilled water cups and it must have come from a tap because it was tepid and nasty. The only other water I had that was bad was at the poly at the Luau, I figure both places were probably using water pitchers filled from the tap.
Everyplace else I just walked up and got a cup of ice water, but I got water at just about everyone, even if I wasn't thirsty. It was September and humid and I figured it was better to be welllll hydrated. So any time I saw a counter without a line I got water. Never was thirsty and I kept a steady pace all week without feeling worn out like you do when you get dehydrated.