In many American locales, especially in areas with access to large clean aquifers, tap water will be cleaner than bottled water. Don't go assuming bottled is better. If you can afford to put a filter on your tap (this is expensive), I would on tap water being much cleaner.
I'd generally recommend avoiding tap water altogether in the U.S. and making sure you're not drinking fluoridated water. It's been show to decrease a child's IQ by up to 4 points when used by pregnant moms[1].