If you were to meet somebody in the middle of the drought in Africa, how would you explain the reason you have, with a plentiful supply of good clean water, that you buy bottled.
Check out this video from Annie Leonard (the story of stuff) and then read the excellent article from Dr Mercola on the bottled water scam.
Then I guess it's up to you and me. Fill your own for a journey or continue to pollute the planet. Insist on tap water in your favourite restaurant and no, don't pay any surcharge for it - they make their money on the food and the wine. Send people to this blog or the excellent Annie Leonard Story of Stuff blog and her youtube video channel for an even greater insight.