Some type of water filtration process will provide some benefits. I wouldn't recommend tap water. You can find some good water filters at http://www.ewater.com.
If you want to take it to a next step, adding a little bit of Terramin clay to liquids can help to bind some toxins that might be present. I haven't seen filters that remove all of these medicines yet. It's a new world. Makes you wonder about what our children will be inheriting?