This is called the overflow drain.
This is a secret passage where the water can go if you accidentally overfill the tub.
Some overflow drains have visible holes or other features, but they all do the same thing.
The Spruce / Michelle Becker
The water entering the overflow drain goes into a pipe that feeds into the main tub drain.
This presents a problem when you better plunge the tub.
Therefore, you must seal the overflow opening before getting to work with the plunger.
The Spruce / Michelle Becker
The best way to seal an overflow is by covering it with duct tape.
Remove the stopperof the bottom (main) tub drain.
You may have to unscrew it or turn it back and forth a little while pulling up.
The Spruce / Michelle Becker
Fill the tub with about 1 to 2 inches of hot water (not cold).
Hot water helps dissolve soap in clogs.
Repeat the same process as needed until the drain starts to flow freely.
The Spruce / Michelle Becker
Remove the Tape
Remove the duct tape from the overflow and replace the drain stopper.
The Spruce / Michelle Becker
The Spruce / Michelle Becker
