When I was in elementary school we lived out in an area dominated by rural farmland. I'm guessing close to 100% of the students at the school got their water at home from an untreated well. Once a month the school nurse would bring around little cups of fluoride mouth wash and we would swish with it for 3 minutes then spit it out.

If you are seriously concerned about fluoridated vs non-fluoridated water there is no reason that the two things have to be linked. Heck, you can get many mouth washes with fluorine in thing. Listerine has a fluoridated version for example.