I just have to chime in here. My family and I have not gotten sick from WDW water, but we do not like the taste. We got the Brita fill and go bottles for our trip last year and fixed that problem.
That said......
We all spend a lot of $ to go to WDW to have a good time, not worry and God forbid, get sick. I am not a doctor, but my suggestions would inlcude:
1 - If you don't like the taste, use a brita or bottled water.
2 - If you think you will have a problem, bring, ship or buy water.
3 - Minimize the amount of caffeine you drink. It dehydrates you which will not help in the Florida heat.
4 - Practice 'Texas walking', stick to the shade!
5 - Take breaks in the airconditioning, see a show during the heat of the day.
6- Wash your hands often.
7- Ask your Dr for Cipro in case you get a bug from the water or off of a surface.
8- As the Boy Scouts say, "Drink lots and lots of water!"
I personally like GlennandAnn's suggestion, lots of beer!
Harold