I have to buy bottled water when traveling to WDW. The first 2 trips down, we drank the water & we all got sick from it.(We have health issues & delicate systems because of it - but even Healthy & Hearty DH had some problems one year) We use bottled for drinking, mixing, making cofee & teeth-brushing.
My doctor explained that it was just the different composition of Flora & Fauna in their water that our systems aren't used to.
So, if you have health issues or are prone to a delicate stomach & aren't used to FL water, be forewarned.
I haven't been brave enough to see if the Brita filters it down enough for our systems to handle. I do know the ice is filtered somehow, you don't get the same taste or effects from the ice.