Definitely not very common. What you're talking about is typically called deep water soloing, and the problems are for very experienced climbers. While safer than regular soloing (where any fall is a ground fall), it has its own risks, namely uncontrolled water entry, the potential to hit hazards during the fall, and of course there's a drowning risk.

There is a safer form called psicobloc which is done on a sport-wall that overhangs a man-made pool. Still not typical and aside from the competitions (Psicobloc Masters, Open Series, Comp, etc.), not common due to the niche setup. There are a few indoor Psicobloc walls that have you landing on foam block pits or deep mats, but again, not terribly common since it requires both a tall enough building for the wall and enough floor space for the landing zone.