We bring full water bottles (wide mouth) into Disneyland and then, as the day goes on, ask for cups of ice water from the restaurants. They are always happy to oblige. We use that water to refill our water bottles. Much less expensive than buying bottled water. Drinking fountains are not an option for us (ever!) because one of my children has a life-threatening nut allergy and you never know what people have eaten before they slobbered all over the fountain.