Science Buddies: "Ask an Expert"

Which is more pure tap water or bottled water? and what is the best way to test this?

I found many different answers to these questions so I am not really sure and I need help.
Thank you

This seems to be an interesting project. Please visit http://www.ewg.org/node/27248 to get information on puity of bottled and tap water. Also for testing please see ehow.com. It gives you different methods of testing water. Please check and use the most economical or easily available method.

sumit