You can fix a smelly shower drain by removing clogs, cleaning and refilling the P-trap, scrubbing away biofilm, and treating any mold or debris buildup. For lasting freshness, regular maintenance like flushing with hot water and using natural cleaners such as baking soda and vinegar helps prevent odors from returning. If smells continue even after cleaning, it may point to a deeper plumbing issue that requires a professional inspection.
There are a variety of reasons why your bathroom smells like a sewer, and the drain in your shower less than fresh, including…
You have a clogged drain
Clogged drains are common. When you have one, the drain is either slow, or doesn't move at all. Clogged drains are caused by a build up of hair, soap scum, dirt, mineral deposits, and even small items that have fallen down the drain. Or, all of the above!
The best way to unclog a shower drain is via snaking. So, if you don't already own a hand auger (also called a plumbing snake) – and you should – head on over to your local hardware store to pick one up.
Place the plumbing snake into the drain until you feel it hook onto something. At that point, pull it out. There should be some gunk along with it. Keep doing this until you've removed the clog entirely. This video from This Old House shows how to use a plumbing snake on a clogged bathtub drain. You unclog a shower drain using the same technique.
You can also try clearing the clog with a plunger, your hand, or by pouring boiling water down the drain. However, we do not recommend using chemicals to clear a clogged drain because they could damage your pipes.
You have a dry, shower P trap
Look under your kitchen sink. See that U-shaped pipe? That's called a P-trap. There's one under your shower drain as well. You just can't see it.
P-traps are shaped like a U for a reason. Their job is to fill with a little bit of water in order to keep sewer gas from entering your home. If they dry out, due to a leak or evaporation, sewer gas can get in. So, grab a flashlight and check to see if the P-trap under the shower drain has water in it. If it doesn't, just run some water. It might have dried out because you rarely use that particular shower.
Your P-trap might also be filled with smelly debris. You can easily fix this by pouring a box of baking soda down the drain followed by a cup or so of vinegar. Let it sit there for an hour or so, and then run water to rinse.
You have a biofilm problem
You know how rocks can be slippery when you wade into a stream? That's because they're covered with biofilm. Tooth plaque is also a kind of biofilm.
Biofilm can also form in your shower. You've probably seen it but didn't know what it was called. Many people refer to is as ''pink mold''. It's not actually a mold though. It's a biofilm. You can get easily rid of biofilm in your shower drain by scrubbing it away with an antimicrobial disinfectant. Do this on a regular basis to keep biofilm from forming.
You have a leaky pipe
Cracked or broken sewer pipes can allow sewer gas to enter your home. If this is the problem, you will might notice that your shower smells like a sewer or like rotten eggs. If so, this is a job for the pros. Contact a sewer repair professional right away.
You have a mold problem
Remove the drain cover and check it for mold. If you see any mold, give it a good scrub with some mold and mildew remover, and then replace it.
You have a cracked plumbing vent
If a vent was completely blocked, your pipes would not drain, resulting in a backup or blockage. If it is partially blocked, the drains could just be slow and potentially you could still have a backup. The sewer smell would only come from a cracked vent. These cracks can be diagnosed with something called a smoke test or a vapor test.
How to prevent smelly drains in the shower
You can prevent smelly drains in the shower by pouring boiling water down the drains once a week. On a monthly basis you can dump baking soda, vinegar, and boiling water down the drains. Think of it as a drain deodorizer!
If none of these techniques are working to get rid of the sewer smell in the bathroom, contact a sewer repair professional and schedule a CCTV sewer inspection to uncover the cause of the problem.Â
