Well, you're getting the microplastics no matter what you drink, so there's no sense really worrying about it. We're basically already fucked there. The best we can do is try to reduce how much is added.
It would be nice if places like Flint at least had a water service where you could go and get a several gallon (or multiple) drinking water tank, that you bring back to get new ones, like propane. People shouldn't be forced to buy bottles. They country/state/nation should be providing an alternative until things can be fixed.