Subject: Wouldn't fusion energy deplete our water sources?

I've read that nuclear fusion could create enough energy for a lifetime with 
only 500 litres of water (from which deuterium is obtained), and 30 grams of 
lithium (needed for tritium). That sounds great, but if that amount is 
multiplied by 6 billion, a staggering 3000 billion litres of water would be 
needed per generation to create enough fusion energy for everyone on earth. As 
far as I know (correct if I'm wrong, I'm no expert) the water needed for 
nuclear fusion is not recycled, but instead, helium is produced.

A lot of people are very enthousiastic about fusion, but wouldn't switching to 
fusion energy simply mean switching from one finite resource (fossil fuels) to 
another, far more important one; namely water?

Re: Wouldn't fusion energy deplete our water sources?