True, but it might depend upon whether you de-flea the dog, smoke, have a scented atomiser etc.Nope. Its full of crap and other airborne collected detritus, so not actually very good for your tank or drinking or washing....
Assuming you don't smoke etc and you have a conductivity meter? If you have, and the water reads below about 50microS, I'd use it.I get about 2L a day out of my old terraced house so seems a shame to waste it. As I understand it's just DI water?