Sneaky Culprit of a Wet Bathroom Floor

Updated: Nov. 14, 2022

As a longtime plumber, I always try to investigate as many possible causes as I can before leaving a job, even when it seems there’s an obvious culprit.

plumbing stack flashing

Always investigate the source

As a longtime plumber, I always try to investigate as many possible causes as I can before leaving a job, even when it seems there’s an obvious culprit. Most often, a wet, swollen bathroom floor right under a toilet is caused by a leak or failing seal. But that’s not always the case.

On this job, the cap was missing on the plumbing stack flashing, a problem that wasn’t visible from the street. Only by pulling out my ladder did I dis-cover the real reason for the wet bathroom floor. Nobody likes crawling around on a roof, but old, dam-aged or poorly installed roof flashing causes many leaks. This homeowner was thrilled that I didn’t just slap on a new wax ring and hit the road. — Les Zell, master plumber