Water dissolves matter, and we're supposed to be 70% water, but living creatures would collapse in a puddle of organic matter if that was true.
What we perceive as water is really compacted air, brought together by the pressure of the lower atmosphere. This is why clouds, an preliminary state of compacted air, can't stay up as soon as they've compacted enough.
While compacted air is technically healthy, our lungs are not strong enough to breathe it, we'd need muscular gills for that.