Fluoridation should not be a blanket “yes or no” thing, for several reasons.
1) Many places already have plenty of fluoride in the water, so adding more is effectively overdosing people with it.
2) Fluoride, along with chlorine and bromide, are increasingly common in our diets and water, and tend to block the bodies ability to absorb iodine.
3) Fluoride is best applied directly to the teeth in toothpaste, not swallowed, and it is now ubiquitous in toothpastes. In the rest of the body it is unimportant at best, and can even be somewhat toxic.
Saving money should also be a reason not to add it, I would rather have lower water/property taxes because they don;t have to add this poison to my water.