Most odors in sink or tub drains aren’t caused by sewer gas, since water in the drain trap acts as a barrier to prevent sewer gas from coming up into your home. Instead, the usual culprit is bacteria growing in organic matter—such as hair—which becomes lodged in the drain.
To remove organic matter and odors from a drain:
- Insert a drain cleaning tool in the drain.
- Pull the tool back out and remove any hair or other organic matter.
- Repeat until the drain is clear.
- Pour diluted bleach or hydrogen peroxide down the drain (one or the other, don’t mix the two together) to kill any remaining bacteria.
Watch this video to find out how.
- How to Clean Out a Tub Drain (video)
- How to Unclog a Tub Drain (video)
- How to Unclog a Slow Draining Bathtub
Allen Lyle: Isolated odors are not uncommon. We get the question all the time, “I’ve got this smell coming from just one sink “or just one tub. What is it?” Biggest fear is that it’s sewer gas. And it’s possible, but it’s not probable. Here’s why.
Under all plumbing, whether it’s an old house like this or a brand new one, you’ve got what’s called the P-trap. What happens, as water drains out of the sink or out of the bath tub, a small amount of water stays right in there, and that becomes a barrier to all of that sewer gas.
So, if you’ve got a crack in that pipe or a leak fix it, that’s probably all it will be. But more than likely, it’s the bacteria. Think about it, washing your hair, shaving, you get a lot of organic matter down a sink, and down a bath tub drain—this is really notorious here.
As you get the clog, bacteria begins to grow. What you need to do is just remove the clog. Easy to do, I’ve got a little zip tool here. We’ll slip that inside.
Once you remove the clog, you want to take a little diluted bleach, maybe some hydrogen peroxide, pour it down the drain—don’t forget about the overflow. That’s going to kill both the bacteria and the odor.