From the sticky:
> Water: [...] but there's no danger in drinking more.

http://en.wikipedia.org/wiki/Water_intoxication
http://medical-dictionary.thefreedictionary.com/overhydration

There even were deaths from drinking too much water. (although I know it's very improbable to die from this)

I'm posting this because my kidneys hurt after drinking too much water. I know it's unrelated as I have another kind of problem but w/e.