Try looking at the back of your toothpaste - if it contains fluoride there's gonna be a warning label saying something like: "Do not swallow," and "in case of accidental ingestion, contact the poison control center."
This poison shouldn't be added to the water supply anywhere!
That's correct. That'y why some of the children's toothpastes are fluoride free because of how often kids swallow it.
I've been using fluoride free toothpaste for years myself and haven't experienced any negative effects, more like the opposite. Can't remember that I've had any blisters since that, no cold sensitive teeth and the tongue looks more healthy ;)