I'm sorry but personally, I'm scared of tap water.
Even though the concentrations of pollutants in the water are very well regulated, I feel that sometimes, the lobbyists from chemical factories have quite a lot of power to convince the regulators to raise the concentration limit of pollutants. Like for instance, the limit of the amount of arsenic in water allowed has been reduced 75% several years ago, so you could imagine before that, people were consuming 3 times the amount of arsenic as they did today.
Of course, something similar could happen today with another chemical.
Simply put, I just don't trust the regulators. The only waters I drink are filtered water, or, if I have enough money to spend, FIJI or Dasani. I understand a lot of people may not be a big fan of Dasani, but I've been to their factories a couple of times and they're very ethical people.