I personally don't know much about this subject. I would venture a guess to say to make sure you test the water thoroughly before using it. You're still going to have to go through the process of cycling the tank, so there is no ammonia and such. The only benefit I can think of initially is probably a lower chlorine content, but I believe you're still going to want to treat the water before hand.
I'm sure someone with more knowledge on this subject will be able to post.