Aloha Michael,
Welcome to planDisney! I have journeyed beyond the reef to answer all of your planning questions.
I see that, like Moana, the water is calling you from all directions. As Grandma Tala said, “In the beginning, there was only ocean,” and it is vital to beat the July suns at Walt Disney World Resort. I’ve had many different experiences with the availability of cases of half-liter water for purchase at the various
Walt Disney World Resort Collection Hotels. Sometimes, I can only purchase half-liter bottles individually, and other times Cast Members can locate small cases in the hidden caverns of the resort gift shops. Since availability isn’t guaranteed, I would recommend speaking to a Cast Member at your resort hotel and asking them what they have available upon arrival. If all else fails, you can purchase individual bottles at any of the resort gift shops. Another option for you if your heart is set on cases of water is having cases delivered to your hotel using a grocery delivery service.
Apologies for not being able to give you a more definitive answer; as the ocean flows, so does the stock of water at the resort hotels.
A Hui Hou and Happy Planning!
Ashley F.