Hi, Deborah!
Welcome to the Disney Parks Moms Panel. You'll be right in the middle of all the magic in just a few days! How exciting! You're very wise to think about staying well hydrated. The Orlando area heats up quite a bit in July with average highs in the 90's and lows in the 70's, and average humidity levels between 40-60%. You'll definitely want to have water with you at all times. When you're touring the parks, I would also recommend mixing in some air-conditioned indoor attractions and shows throughout the day to escape the heat.
You're going to love staying at Disney's Beach Club Resort! Don't miss the amazing Stormalong Bay swimming complex -- it's worth spending a morning or afternoon there relaxing and cooling off in the lazy river. As for beverage options, bottled water is available for purchase at the
Beach Club Marketplace, a sundries shop and quick-service food location (with hot breakfast items, sandwiches and wraps, soups and flatbread pizzas) that also offers grab 'n' go items. Beach Club Marketplace is open from 7:00 AM to 11:00 PM daily.
You may also purchase a refillable mug for coffee, tea and soda which is valid for the duration of your stay. Hurricane Hanna's Grill, the poolside bar, also participates in the refillable mug program.
When my family visits Walt Disney World Resort, we always bring our own refillable Camelbak water bottles. We refill them at the water fountains located in the parks. When we stop for a meal at a quick-service dining location, we also ask for a cup of ice water to refill our bottles.
Wishing you a magical vacation! Enjoy your "Disney Time" with your family, Deborah!