I ran into that in real life.

I had a plumbing problem in my house. I had a sink that was randomly filling up with clear cool water. When I used the sink it worked fine. Now I'm pretty handy, but I had no idea what was causing that to happen.

So I called a plumber. I showed him the problem, and he immediately knew the cause. The condensation drain line for my AC ran to that sink. He suggested snaking the drain. He was there 10 minutes but that fixed the problem. He charged me $175 which was his minimum. I gladly paid it. I didn't view it as paying $175 for the fix, I viewed it as paying $175 for his expertise.