Someone, I can't remember who, passed on a great tip which has saved us hundreds of dollars and loads of hassle over the years.
In all the parks, the cafes and restaurants give out free beakers of iced water. No strings attached, free HUGE beakers, as many as you want.
You don't even need to queue up, simply politely make your way past those queueing to buy meals, and ask nicely at the counter.
The water is usually pretty chlorine-free, as it comes filtered out of the same machine that makes up the sodas. If the taste doesn't suit you, then buy sachets of sugar-free Crystal Lite from any supermarket or pharmacy, many flavours available.
When your thirst is slaked, chuck the beaker in the bin, and nothing to lug around.
Marvellous! Hassle free holidays, just the job
VV