The tap water in North America is for the most part very good. We have excellent infrastructure and the water is safe because it is chlorinated.
The problem is though that many people don't like the taste of chlorine in their water. In their minds they frequently equate chlorine with other toxic chemicals. If you held a blind taste test in any major N.A. City and served de-chlorinated tap water vs. any brand of bottled water, it would be doubtful that very many people would be able to tell you which was which.
From this we can conclude that people drink bottled water because it doesn't contain chlorine, and because of the fervent marketing efforts of the bottled water companies. I say forget bottled water.
Buy a nice stainless steel Klean Kanteen sport bottle (to avoid the Bisphenol A in polycarbonate bottles) and filter your tap water to remove the chlorine. Plan ahead and keep a jug in your fridge. If you don't want to refill your sport bottle from the gas station bathroom when you are out and about you can always buy a refill of cold, safe, filtered tap water from an eco-friendly machine like the one from watervend.com.
Every sport bottle of water you drink is one less water bottle made, hauled, recycled or discarded. Don't forget to run your sport bottle through the dishwasher once in a while.
Enter your city or zip code to get your local temperature and air quality and find local green food and recycling resources near you.