The worlds population is only 6 billion, not 7 billion
Water isn't a problem. Water is naturaly recycled bck into the water cycle. If I remember correctly when your body uses water, it puts a large percentage of your "water" into the toilet. From the toilet it goes into a sewerege system, or like ours, it goes into an underground tank that purifies it until its drinkable. Then it just empties it onto the lawn somewhere, where a huge percentage is recycled, etc.
It seems like most greenies these days, are worried about the world flooding from the polar Ice caps melting. I completly disagree that the world is flooding, and that the world is drying up.
Water has always plentiful, and is still plentiful today; you can't look at the Sarara desert and say "oh no, the world is drying up"

when you havn't even seen the rainforests of Brazil "oh no, the world will flood, there is too much rain here"

My honest opinion is that people arn't draining the earth of water. Or causing the world to flood. And I'm sorry if I sounded abit mean, I'm just trying to make a point