Err, I say exactly the opposite myself. I hate treated water from a public water system. All those chemicals (and whatever comes off the piping) are far from tasty.
Depends on where you live. In the Netherlands, I don't think you can taste the difference or people even prefer tap water, because it tastes more neutral then some mineral waters. Sourcy and Bar-Le-Duc are even bottled from the same source as Utrecht gets its tap water from. Main difference with US is no chlorine is added.