Why Does My Shower Drain Smell? Causes and Troubleshooting

Every now and then, doing something as simply stepping into your bathroom can end up revealing a nasty smell coming from your shower. 

Even though the shower itself is clean, the smell is still coming from it. Giving it another clean can help, but only for a short time. No matter what you try to do, you always end up back to the same question: why does my shower drain smell?

In many cases, the reason your shower and its drain smells is far less of a severe problem. Quite a lot of soap and shampoo goes down into the drain, mixing together with all that dirt and hair as well. The result is four potential causes of the smell, one of which is a relatively simple plumbing issue. 

We do cover all of these causes and how you can go about finding or even fixing the issue in this article.

However, if you’d rather call a professional plumber for help or if you think the cause is far out of your reach, Diamondback Plumbing is here to help! Just call our team and we’ll be there as soon as possible.

Your Shower’s P-Trap is Dirty

One of the possible reasons that you might be getting a smell coming from your shower drain is due to the P-trap being too dirty or even dry. To better understand what’s causing the issue, knowing what a P-trap does is important. 

Simply put, a P-trap is a small section of piping that’s shaped like a U or a P when connected to the rest of the plumbing. Much like kitchen and bathroom sinks, your shower also has a P-trap for many of the same reasons. 

Though a shower’s P-trap is much further down into the plumbing, all of them are designed to prevent bad smells from shower drain fixtures by holding water inside it. 

However, when that water dries out or the P-trap gets dirty, the smells can end up coming back up the pipes and into your bathroom. If you want to deal with this yourself, the best way is to check the trap in your basement. If you find a U-shaped pipe, turn off the water and carefully disconnect it. 

Otherwise, simply running the water for a few minutes can flush out dirt and add fresh water to the pipe.

Your Plumbing Is Leaking 

In many cases, the answer to “why does my shower drain smell?” can be found in the state of the plumbing itself. Though rarer than the other causes, leaky plumbing can also be a more severe issue. Depending on where the leak is, getting stenches like sewage or rotten eggs can often mean sewer gasses are coming up, making the situation dangerous without professional help.

Fixing the leaky pipe can also be easy or hard depending on a few factors. Given that you have direct access to the pipes themselves, how you can go about doing repairs depends on the pipes’ materials. If you don’t smell any sewer gasses and the pipe is made of PVC or a similar material, there are many types of waterproof tape and kits available that you can use. 

On the other hand, pipes made out of cast iron and similar material need to be replaced completely.

You May Have a Drain Clog

Possibly the most common reason that you might be getting a bad smell coming from a shower drain is a simple drain clog. As mentioned before, shower drains see quite a lot of soap and shampoo going down into the plumbing. If it lingers and even dries out before the wastewater can push it away, the dirt and soap can end up forming a clog. That clog can often give off bad smells as a result of its components.

As you might already know, there are many different ways that you can get rid of a clog, each one varying in effectiveness depending on how deep into the plumbing it is and whether it’s a full clog or not. 

Drain cleaners are by far the most effective at cleaning out clogs, but they also come with the risk of damaging the pipes. Choosing a good, chemical free drain cleaner can be just as effective though!

If the clog is closer to your shower and seems to be a partial clog – though the type of clog doesn’t fully matter – a drain snake or hand auger is a great choice. Though it can take a few attempts to get the entire thing out and it can be nasty to some, drain snakes have no way of accidentally damaging the pipes. 

More often than not, though, the nastiness is a fair price for removing the smell coming from shower drain fixtures.

There’s a Biofilm Build Up in Your Pipes

The last possible answer to “why does my shower drain smell?” is due to an excess of biofilm. Often, many people describe biofilm as a type of slime, muck or mold though it actually isn’t. Instead, biofilm is a colony of bacteria mixed together with its waste. All of it is held together by a slimy, glue-like substance. 

Though it can be nasty at first, you might have already experienced biofilm when looking at the plaque on your teeth. It too can be considered biofilm too.

Since bacteria and waste are often a big part of biofilm, bad smells are almost a given. However, since there are a large number of different kinds of bacteria, there are similarly many kinds of biofilm. 

Cleaning them away is much the same though. Simply use a fuzzy paint roller – preferably an old one – dipped into a cleaning product or disinfectant. Push it into the open drain, twist it around and pull it back out. Repeat the process until you see no more residue on it.


The main reason that your shower drain might smell off can be one of any range of causes. Though the most common is often a clog mixing with dirt and other materials, there are still more organic reasons to consider. 

Whatever the cause is, finding and fixing the problem, no matter how deep into the plumbing it goes, can solve the problem. If you do think the cause is out of your reach, just contact our team at Diamondback Plumbing today.

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