My school chemistry is pretty rusty, but I'm fairly sure it's not a good idea to drink distilled water. Will try to find out and come back if I find anything on it.
I buy this from time to time. Some chemists shops will sell it to the public (in 5l containers). Out of a dozen chemists in our town, only 3 do. You could ring around to save your feet (and time). I usually get charged between 5 and 7 euro. Btw they use it to make up liquid medicines eg for kids, so obviously it's safe to drink.