If you can figure out a better filtration system than your competitors here: http://coffeetea.about.com/od/water/tp/waterbottles.htm -- you may have a more viable idea than you think.

Tucson's tap water is pretty bad. It's chlorinated mineral water combined with a highly mineral ground water. I drink brita at home, but it's a pain on the road. However, I drink the tap here. When I go to Phoenix, I have trouble even drinking the tap, it tastes so bad in areas.