Just out of curiosity. Does the expression "inspect the plumbing" soundsI haven't heard of it, but I figured it out right away. I suspect it's a polite euphemism, something like "I'm going to powder my nose." It's a way of indicating that you plan to go use the toilet while not actually saying so directly. If you're going to head to the bathroom, you might say "I need to inspect the plumbing" as a tongue-in-cheek way of providing an excuse for going to that room.