Great question - and I would encourage people to get off of tap water AND plastic bottled water. It's best from the "health nut" vantage point to get BPA-free bottles - the hard plastic ones, and get them filled with either the distilled or reverse osmosis or spring water. If doing RO or Distilled, some people feel it's best to add back some minerals. There are a lot of chemicals in tapwater, and the body already has enough to deal with. :)