This is what can happen if a water leak is not addressed. It was much more expensive to repair than it would have been to call a plumber. This was an investor owned property and the investor knew there was a water leak. Over the months of showing the property, the water was turned on at some point and a slow leak in the piping resulted in a massive clean-up project. Eventually, the plumbing was repaired and all the damaged drywall was removed. It was a pretty big job and a lesson for the investors. When your inspector reports a leak that needs to be addressed, don't ignore it!