I am a Toxicologist and I drink tap water unless I want to buy some bottled water sometimes for convenience. And, from now on I will drive down to S. Utah to get that bottled water from your Chevron Tanya.
For fluoridation it depends on the natural levels. Some areas of the country have high levels of natural fluoride and some areas have very little natural amounts. One should be trying to achieve a specific level and not just more is better. However, I say that having no idea what the natural levels are here. I demineralize my teeth with 8 diet cokes/day and call it good.
IntrepidXJ is right about anything being toxic. That is the entire basis for Toxicology and the theory came from a 15th century Swiss doctor named (and I'm not kidding with this)
Philippus Aureolus Theophrastus Bombastus von Hohenheim