I believe their policy for Volcano Bay is the same as their resort-wide policy, which is:
Know Before You Go
We offer a variety of food options at restaurants and concession stands throughout the resort. However, we understand that you may need to bring outside food and drinks into the parks. Please note the following guidelines:
Acceptable items:
- Bottled water
- Small snacks that do not require heating
- Any food required for medical purposes and medically indicated nutritional supplements
- Any food required for special dietary needs
- Baby food/baby formula
- Soft-sided insulated bags no larger than 8.5" wide x 6" high x 6" deep
Prohibited items:
- Alcoholic beverages
- Picnic lunches
- Food that requires heating or refrigeration
- Glass containers
- Hard-sided coolers
- Soft-sided coolers larger than 8.5" wide x 6" high x 6" deep
- Suitcases and bags with wheels
- Folding chairs
- Clothing with offensive language or content
- Clothing that represents someone as emergency personnel
- Weapons of any kind
Please be advised that all bags and personal items are subject to inspection.
There are water fountains by just about every restroom and I believe at least some of them would accommodate a water bottle.