ALL drinking water in the US is under *local* control by those who receive and drink the water, produced by their *local* water district treatment plant ... and has been for ... ever?
That means that at any time .. a local petition driven initiative campaign calling to stop any *artificially added* fluoridation of their water by their local water district treatment plant (some water tables have natural presence of fluoride) can be put to vote and if passed ... goodbye fluoridation at *that* plant.
Some water districts don't fluoridate the water they produce. Mine doesn't for instance. You can call them and ask .. they'll even send you their latest chemical breakdown report of everything they've done to the water.