There may be a very simple evolutionary reason why water does not really taste of anything, as I learned from the psychophysicist Mark Changizi. Pure water has no taste because our taste buds have been calibrated, very sensibly, not to notice it.

For a few million years, the most important contribution taste buds made to survival were to detect things in water that weren’t water: the very things, in short, which might indicate that the water wasn’t safe to drink.