there is more fluoride in the food when eating out than in the water, like 100 to 1000 times as much. stuff life farmed shrimp is practically soaked in chlorine. chlorine is also used liberally in all comercial kitchens.
there is only one way to have a clean diet. stop eating. drink only distilled water. add to that as needed and investigate it all, eat only raw, prepare it all yourself. otherwise, that glass of city water doesnt mean a thing. have a coke with your lemon. you do more damage worrying about it. the thing to do is not eat out at all.