If you live in one of those areas you're far better off with a filtration system than regularly purchasing bottled water which is also not in any way guaranteed to be safe.
It can take a lot to filter water safely. The classic carbon filter under the sink does very little to improve safety, even reverse osmosis can fall short. So, while you can make things safer it's far more difficult than many assume.
There is also the danger of microplastic particles acting as endocrine disruptors. This is a rapidly developing field within (eco)toxicology and is of growing concern among environmental scientists.