Hey howdy hey Judy and welcome to planDisney!
Disney's Boardwalk Inn has to be one of the more underappreciated resorts in my opinion. We love the
Boardwalk and the entire area. So many cool little shops, beautiful scenery and so many delicious food options are all so close. It is a great way to spend an evening in Walt Disney World Resort without visiting the parks. Like you, there are some conveniences that we like having quick access to in our rooms that we are sure to stock up on or have delivered to our resort so we have them available. Water is one of them!
As far as buying a case of it in Boardwalk Inn, your best bet will have to be at the Screen Door General Store located on the Boardwalk. They have water for sale, I am not sure you will be able to buy a full case of water there though. One thing that we do to get our snacks and things for our rooms is to have them delivered by a grocery service. We always use "Amazon Prime Now" for the food and snacks and this works out great. They will deliver everything to Bell Services and you have the option to pick them up or have Bell Services deliver the items to your room for a small fee. I have many friends that use "Garden Grocer" or "Instacart" and so many other options for grocery delivery in Walt Disney World Resort that you have some great options.
One of my family's favorite plans of action is to visit the
Boardwalk Bakery for a quick breakfast option on our way towards EPCOT for the day. EPCOT being a quick walk allows us to enjoy our breakfast while we stroll on over! I hope you have a great vacation at the Boardwalk Inn. If you have any other questions let us know, we love talking about all things Walt Disney World.
Happy planning,
Nick