Hi there, Latesa, and welcome to planDisney!
I love this question because I've personally witnessed an "oops" moment when it comes to this topic. I once invited a friend to Disney World who had no idea that she could bring their own water bottle into the theme parks. If I had been paying attention to the fact that she was bottle-less, I totally would have said something. But the story had a happy ending, and it's my pleasure to share the tale.
First things first: Yes, you may bring a personal water bottle into the theme parks. Sometimes I stick a plastic water bottle into my Loungefly backpack or bring a full-on stainless steel bottle. Going by the official
Walt Disney World Resort Property Rules, the biggest "no" is that the water bottle can't be a glass container. Although I usually bring bottles that are small-to-medium sized, I've brought a mega 73-ounce jug a few times. But, trust me, the smaller the better because you won't want to lug around a huge container all day.
AN EXTRA GEM: Remember that I told you that my friend's story had a happy ending? Well, at the theme parks and water parks, you'll find plenty of
casual dining locations and snack stands where you can find complimentary water cups. They're always nice and cold, which is perfect for the toastier Florida days. If you do remember to bring your bottle, there are several water refill stations throughout property as well.
Thanks again for stopping by, Latesa. Please don't be a stranger if you have any more questions about your upcoming visit to The Most Magical Place On Earth.
Any planDisney panelist will be more than happy to share their tips and tricks with you.
Magic always,
LeAndra