Hi there, Alidia, and welcome to the Disney Parks Moms Panel!
Bringing a Hydro Flask or similar metal water bottle is a great way to keep your water cold throughout your visit to the Happiest Place on Earth! I'm happy to report that you shouldn’t be required to pour out and empty your water bottle when passing through security on your way inside the Resort. However, a Cast Member at the security checkpoint may ask to open your bottle to check its contents, since metal water bottles are opaque. Just keep in mind that alcoholic beverages and glass containers aren’t allowed inside the Disneyland Resort, as stated in the Rules. Also, here’s a helpful article from the Disney Parks Blog about the latest rule changes coming to the Disney Parks starting May 1, 2019, covering everything from ice to strollers!
Once inside the parks, you can refill your water bottle at any of the drinking fountains located throughout the parks, or, you can ask for a cup of ice water at any quick-service dining location. Staying hydrated is especially important as the weather starts heating up! I have a few more suggestions for beating the heat this summer… including checking out the brand-new attraction in Disney California Adventure Park's Hollywood Land, Mickey’s PhilharMagic. It’s a 12-minute 3D movie in a beautiful air-conditioned theater, and even little Mouseketeers are sure to love it! Also, don’t miss the refreshing slushy drinks being served now at Ramone’s Serv-ice Station in Cars Land! It’s located on the back side of Ramone’s House of Body Art, next to the Radiator Springs Racers entrance.
Wishing you a magical Disney day!
Kristin