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How To Remove Sewer Smell In Bathtub Drain

How do I get rid of a horrible sewer smell in my bathtub drain? The bathtub drain has odors coming out of it. This smell only happens intermittently and only in a particular bathtub drain. The bathroom that smells is in the guest bathroom and it does not get used often.

This is a single story home and the smelly drain is near the washing machine laundry room. It seems to happen more in the summer humid months when the AC is running. Knowing all this information what do you think can be causing the odors?

How To Remove Sewer Smell In Bathtub DrainHow To Remove Sewer Smell In Bathtub Drain


In your case, a smelly bathtub or shower drain is sewer gas. This issue may be with the venting system in your home. If the bathtub drain is near the washing machine, the vent pipe in the system for the washer may have a clog. The venting system in your home is designed to keep water in each drain trap to block the sewer smell.

If the vent pipe is clogged when the washing machine drains, it may be causing a suction issue where the water is pulled out of the drain trap in the bathtub drain. When the water is missing from the drain trap, the sewer smell gets through and stinks up the bathroom.


To fix this issue, the venting system in your home needs to be inspected. A temporary fix is to slowly pour some water down into the drain to refill the drain trap and block the smell. A small amount of mineral oil poured into the bathtub drains that are not used often will help to slow the evaporation of water out of the traps. You can also put a tight plug in the drain to block the smell temporarily.


If you have access to the bathtub or shower drain from below such as from a basement, check to see if the bathtub drain has a p-trap or an s-trap. A p-trap is where the water will sit to block the smell. If the p-trap is missing, the smell gets through because no water is sitting in the pipe to block the smell. Missing traps or vents will cause odors.

Bathtub drain p-trap uses water to trap sewer smellBathtub drain p-trap uses water to trap sewer smell

NOTE: This is a specific venting problem that may not be the case for most people. In many cases, there may be a simple clog in the bathtub/shower drain line that is causing the sewage or rotten eggs smell.


A normal clog in your bathtub drain may be because hair, soap, and other residue is creating gunk in the drain line. Particles and other debris can get clogged in drain pipes and bacteria can build up. When this happens, an a smelly sewer odor is released into the bathroom.

If this is the case, unclogging and cleaning the drain line will be sufficient.

Clogged bathtub drain uncloggedClogged bathtub drain can be cleared


  1. Use an enzyme drain cleaner or other proven drain clog remover
  2. Follow directions on label or add 1 tablespoon of enzyme cleaner to a quart of warm water
  3. Slowly and carefully pour the quart of enzyme cleaner into the clogged bathtub drain
  4. Let the cleaner sit and eat away at the clog for 24 hours or more
  5. While letting the enzyme cleaner do its job, do not use the bathtub or shower
  6. Repeat this every 24 hours until the sewer smell and the blockage is alleviated
  7. The enzyme cleaner “eats” away at the blocked drain clog and will also remove the sewer smell


DISSOLVE Liquid Hair & Grease Clog Remover Drain OpenerDISSOLVE Grease Clog Remover – Drain Opener


Turning the heat up on your water heater can kill the bacteria and can fix the smelly drain problem. The average water temperature setting is from 120F to 140F degrees. If you temporarily increase the temperature to 160F degrees, this may kill the bacteria and stop the smell. Do this with caution as HOT water can cause scalding.

Water heater temperature electric controls

Water heater temperature gas controls

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Do you have questions or comments on a smelly drain line? Please leave a message below if you have a smelly drain line you need assistance with.

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1 thought on “How To Remove Sewer Smell In Bathtub Drain”

  1. I just added an upstairs bathroom to my home and there has been a nasty smell coming from the tub drain ever since. These lines are new so what else could be the problem besides clogged pipes or bacteria growing? Could the smell be coming from the other pipes we have connected to our other bathroom since they are all connected in one way or another and end up in the same place at the end?

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