I use a filter for water. I grew up on well water, and water out of the tap does not taste right to me. I’ve tried bottled water (the big bottles) when I didn’t have good access to a filter, and some of them don’t taste right either.
One problem with the reusable thermos-style water bottles that people have for sports is that they’re hard to wash unless you have one of those sponge on a stick things. I think if we had reusable, good quality water bottles that were easy to wash and easy to carry around (maybe add a clip on the bottle so could clip it to a purse or something), people would use them more.