Hi --
We drink a lot of water and are usually pretty picky about the taste, and we had no problems at all with the water on Deck 9. We took our own bottles and filled them up as often as we needed. Also, the cooler in your room is a good place to have a bottle or two stored so you'll always have something cold to drink. If you have some kind of small insulated carrier you'll do fine even on excursions -- believe it or not, even after being out on the beach for a good portion of the day (in July!) the insulated cooler pocket of my fanny pack worked great, that bottle stayed cool until I was ready to drink it. It wasn't exactly icy cold, but it sure was better than the hot water most other people were carrying around!
Take care and happy cruising!
Elly