You expect the bad odors in the bathroom to come from the toilet. So when the sink drain starts giving off noxious smells, it's normal to be a bit alarmed. Rest assured that this is a common problem. In most cases, you can take care of it yourself or your plumber will be able to fix it within a few hours. Here's a look at the possible causes of stinky bathroom sink drains and what you can do about them.
Soap Scum and Partial Clogs
Many people don't realize there's buildup in their drains until the drain clogs completely. But there's a period of time before a sink clogs when soap scum, hair, and other debris has begun to accumulate and line the sides of the drain pipe. This buildup often starts to mold and breed bacteria, giving it an odor.
Since a partial clog is the most likely cause of a stinky bathroom drain, try this remedy first. Slowly pour a pot of boiling water down the drain. This will help melt away greasy or soapy deposits and also kill bacteria. Follow the boiling water with a few cups of white vinegar. This should help kill any remaining bacteria and mold.
Dirty Pipe Trap
If your sink still smells, then there's a chance that some offending material has become stuck in the pipe trap. This is a bend in the drain pipe beneath your sink that's designed to catch foreign objects if they are accidentally rinsed down the drain. Typically, you don't send much down a bathroom drain that could get caught in the sink trap and emit odors, but if someone decided to rinse some food scraps or other material down the drain, this could be to blame.
To clean the sink trap, place a bucket under the sink. Then, unscrew the bent segment of drain pipe. Dump anything in that section of pipe into the toilet, and then clean it with some bleach water. Re-attach the bent section of pipe.
Blocked Sewer Vents
If clearing the pipe trap does not work, then your sewer vents might be clogged. These are vents, located on the roof, that allow air to escape from your sewer lines. If they become clogged, the air has to go somewhere -- and depending on the layout of your plumbing, your bathroom sink might be where it's flowing out.
Clearing the sewer vents is a task best left to your plumber since it requires climbing on the roof. Once they clear the vents, they'll probably install mesh screens over the vents so they don't become clogged again.
For more help treating a smelly bathroom drain, speak with a plumber in your area from a company like Authority Plumbing and Drain.