Bad odors from drains, whether in your tub or in a small bath vanity, are generally caused by some sort of blockage in the P-trap (or lack of a P-trap) in a drain. A P-trap is a U-shaped pipe under the drain. Its purpose is to hold water in the bottom of the trap to keep sewer gas from escaping through the drain and into the house. If the P-trap is installed in your drain, you may have something caught in the trap. This is a more common problem than many realize and easily fixed. In a previous post, We discussed removing hair clogs from tub drains, and generally, that’s what you’ll find. You can remove these using a drain snake or chemicals (liquid lumber, etc.) to eat away the clog chemically. After this, you should have no problems. If you do, you may not have a P-trap installed and would need to install one to stop the odor.
Contributed by:
Randy Ritzenthaler