Hi Nyree!
Welcome to the Disney Parks Moms Panel! Thank you so much for finding us hEAR and asking this great question. Staying hydrated is oh so important when you're having fun in the sun at the Most Magical Place on Earth! I absolutely approve the plan to carry a refillable water container with you. And thanks to Disney's environmentally, more and more water bottle refilling stations are starting to pop up all over the parks. Some even in the middle of attraction queues right where you wait!
I just grabbed one of our super cute Resort Refill Mugs from a previous
Disney Dining Plan and filled it with water. It holds 16 ounces, and interestingly enough when the mug was completely upside down, and I held it like that for a full minute, absolutely zero drips came out. I really, really did not think that was going to be the case and I'm really glad that I did not put money on it. However. When tilted in any other angle (as in when turning it upside down and then right side up) there was leakage that ranged from a few drops to "is the lid even on?". While the main part of the lid with the holes snaps on really tight, the rotating cover was not designed to be leak proof. If you were to put these mugs in a stroller cup holder not filled to the brim, which is what I do for my preschooler, they'd be fine. But I wouldn't trust it full or even somewhat empty in a bag, especially since bags ride attractions with their owners.
If you plan on visiting in a hotter month, I do think that you'll be glad that you brought a bigger, more insulated water bottle that can be filled with ice and keep its cool all day. No matter what container you bring, look for
water fountains and bottle refill stations near restrooms. Should you need a refill on ice or ice water during the day, Cast Members at
Quick Service Dining Locations would love to give you a complimentary cup. And don't forget to fill up before you leave your
Disney Resort Hotel; there are usually industrial sized ice machines near the elevators of most Value and Moderate Resort Hotels, but you're also more than welcome to utilize the ice and water at your Resort Hotel Quick Service Dining Location too.
I hope this helped to plan your upcoming Disney Days, Nyree, and if you have any more Walt Disney World Resort vacation planning questions, We're All Ears!
~Kristen