You can order water from any of the grocery delivery services like Garden Grocer, from a company like Staples, from
Amazon Prime Now etc. You can buy a case of water at the resort gift shop, but you would have to transport it to your room yourself.
We order from Garden Grocer. It started as water being our primary need. But we now use if for breakfast items for the room, beer and wine and evening snacks.
Garden Grocer has a $40 minimum and a $14 deliver fee. I saved the deliver fee just over the cost of bottles of water in the parks.
We order juice, coffee, bananas and other fruit, breakfast pastries, beer, wine, soda, water, cheese & crackers and other snacks. Having a quick breakfast in the room saves both time and money. Have adult beverages and evening snacks is great on the balcony. And we have water to carry to the parks
Have a Great Trip