From everything I can tell, each American water heater is what scientific types call a chaotic attractor. But then some buckethead comes along and drops a big, heavy water heater into the middle of the trampoline. The trouble rolls into the low spot and crowds around the water heater.
Water heaters are trouble attractors mainly because they're so screwed up themselves.
Candidates are drilled, over and over again, on the wrong way to do things. Attach a piece of copper pipe to the valve and run it straight down. Cut the pipe off about a foot above the floor. But I'm here to tell you, buckethead installers find dozens of ways to screw this up. Or they run the dang pipe uphill, which will block the outflow.