Probably not ruined. Was it done fermenting? next time use an airlock. You should be ok, RDWHAHB, but a chance in temp caused a changed in pressure and it sucked up the water. But unless the water jug was ridiculously dirty, it should be ok.
Yo, What's Wrong With The Beer We Got? I Mean the Beer we got drank pretty Good Don't It? I Ain't Never Heard nobody complain about the beer we have..... It Drank Pretty Good. Budweiser...What's the name of some of them other beers ?