I've heard some kind of story that after the Romans would conquer a new village or city, they would pour wine (or other alcohol?) down the wells to kill the bacteria and make it safe for future drinking. Has anyone ever heard of such a story?
If you heard that the pouring of wine was to kill bacteria, you know it's a fake. You have to wait till Louis Pasteur for bacteria. Also, unless there was a whole lot of wine/alcohol poured, it would have no effect whatsoever on the water in the well. Wine was very expensive in Roman times -- up to several slaves for a barrel in Gaul around 50BC as Caesar tells us -- unless I remember wrongly the source but I am fairly sure it is Caesar. If Roman were indeed doing so, it would have had nothing to do with making it safe for drinking.
Any wine pouring must have been symbolic or/and religious. Sadly, I do not know of any sources for this.