Origin of the Russian word for water "voda"

Question

The most of sources I encountered (Vasmer, Mellory-Adams etc) assert the Russian word "voda" "вода" originates from the same PIE root as English word "water", i.e. from the PIE form u̯odr. This is allegedly supported by adjective водный which indicates that the PIE word had the r/n stem (-r in Nominative and -n in other cases, this is common for very archaic stems in PIE).

But recently I encountered with a person who seems to be very much confident that the word is a borrowing from proto-Germanic wađan (which gave also the English "wade"). He cites Winter's law and claims that the idea that voda is related to water is outdated.

So who is correct?

Answer 1

There are so many evidences of that Russian "вода" and English "water" are produced from u̯odr/wódr̥ that it will be very strange if the person you've encountered is right.

First, Proto-Slavic "voda" is at least as old a root as the one that forms wađan.
Second, the number of parallels with other PIE languages are striking - even with those of such languages that diverged from PIE trunk independently from Germanic languages. I'm speaking not only about the fact that all these derived words relate to water in wide context, I'm speaking about the fact that the history of phonetical evolutions of these words conforms with everything we know about PIE phonetic events at all (Armenian "գետ" (get) for river, Lithuanian "vanduo" for water, Hittite wa-a-tar for "water", Tocharian "war" for water and so on).

Third, in all Germanic languages water is some variation of "water" actually. It would be kinda strange if Germanic and Slavic word used for designating exactly the same and sounding exactly the same wouldn't be related (though in history of languages such things happen, this is not the case).

PS I'm starting to think that questions of the type are more welcome on linguistics SE.