For the sake of the joke, yes. As long as the water remains pure. But once some of the material starts to dissolve into the water, then it's no longer safe.
Getting it off the floor helps a lot. I used to work in an office with carpet, and when we got new PCs I sat the keyboard box on the floor and put the PC on top of that.
Might not be that bad. My computer picks up way less dust sitting on my desk surface than it did when I had it on the floor, and I imagine OP's TV is mounted at least as high as that.
I'm personally worried about the GPU's heat harming the wires over time. I would've mounted it vertically, but I've never seen custom extensions that do that.