clean shower floor with water on it after shower drain smells was cleaned

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It’s often a big disappointment to prepare yourself for a relaxing shower or bath, only to be greeted by a stinky shower drain smells. Since those problems don’t go away by themselves, you have a little investigation to do to know what caused the odor and fix it.

Image of clean shower floor after shower drain smells were cleaned

Lucky for you, we have exactly what you need! We’ll give you a heads up about the causes of a smelly shower and how to deal with it. All you have to do is read on!

What Causes a Smelly Shower Drain?

Many issues can cause a poor shower drain odor. To name a few, you may have a clogged drain, dry p-trap, or biofilm buildup. Each problem has its own solution, and some are pretty easy. Accordingly, you can try them on your own. Let’s learn more! 

1. Drain Clogs

One of the leading reasons for shower odors is a clogged drain. If you notice that your water is draining slower than normal or not at all, then you’re probably dealing with drain clogs.


Many factors can cause a clogged shower drain, like the accumulation of soap scum, hair, sand, or mineral deposits. Those depositions, especially soap scum and hair, may even combine and cause bigger obstructions in your drain. Luckily, it’s easy to dislodge and get rid of them. You can read more home cleaning tips here.


You can unclog your shower drain in many different ways. If you don’t want to use chemicals, you can snake the drain using a hand drill, also known as a snake. First, make sure that your drain snake is ¼-inch so it can curve smoothly through your drain pipes. You have to be careful, though, because any mistake can damage your pipes.

If you don’t know how to deal with a drain snake, you can go for boiling water. All you have to do is pour a small amount of hot water down the drain to help move the obstruction. If it moves successfully, the shower drain odor will vanish in a few minutes.

If this solution doesn’t work, you can purchase a chemical cleaner from ayn store and pour it into the shower drain to dissolve the depositions. If you don’t mind manual procedures, you can also pull the clog out by hand if it’s reachable.

Woman cleaning shower drain smells with steam cleaner

2- Dirty or Dry P-Trap

If your shower drain smells like a sewer, you’re probably dealing with a damaged P-trap. When a P-trap doesn’t work as it should, it doesn’t block sewer gases; therefore, your bathroom will smell musty.


The main function of P-traps is to hold water constantly to keep gases away from the sewer line. If your bathroom starts to smell like sewage, then the P-trap isn’t holding enough water. This can be caused by two possibilities, the first being that you haven’t used your shower for a long time, so the water evaporated.

Then, the second option is that you have a problem with your plumbing system. This may be caused by breakage or a blockage in your vent stack. On the other hand, if you don’t smell sewage, you’re probably dealing with a dirty P-trap, which is quite common.


If you’re dealing with a dry P-trap due to rarely using your shower, you can fix the problem by leaving the water on for a while. Conversely, if you use your shower normally, you need to contact a professional and get a check-up of your plumbing system. This is all for a dry P-trap, but if you suspect that your P-trap is dirty, you can easily clean it. 

Just pour half a cup of baking soda down the drain along with half a cup of white vinegar. Next, put on the drain cover and let them settle. You’ll hear a fizzing sound for a while as the baking soda is doing its magic. This will guarantee you a clean shower drain. 

Also, you can seek professional drain cleaning if you don’t want to bother with home remedies.

3- Biofilm Buildup

Biofilm buildup is a common issue in bathrooms, often causing an annoying musty odor as a result of growing mold. To clear things up, a biofilm consists of a group of bacteria held together by a layer of a glue-like substance. It grows on surfaces like rocks, pipes, and showers, and it causes an odd shower drain smell.

Since biofilms can harm you, you need to take care of them as soon as possible. Otherwise, they may cause health issues like infections in open wounds and urinary tracts.


You may think a hygiene issue causes biofilms, but you don’t have to blame yourself because they grow in hard-to-reach places. For instance, mold may develop on the inside of shower drains, causing quite an unpleasant smell.

Unfortunately, bacteria types are countless, so you may be dealing with multiple types of biofilms at once. The most common type that appears in bathrooms is Serratia marcescens. Although it isn’t a mold, S. marcescens is called pink mold. This is because it forms a pinkish-orange biofilm.


If you have orange stains in your shower, you can easily clean them using an old toothbrush. Just scrub the stained area thoroughly. After doing so, wipe the surface with antimicrobial substances to disinfect the area. This will efficiently kill mold and bacteria growing in your bathroom.

You can also follow the same process on your shower tiles. To prevent the biofilm from growing back, do it weekly. If your bathroom still has odd odors, they may be coming from a dirty drain.

To thoroughly clean your drain from the biofilm, remove the drain cover and wash it. Next, soak a paint roller cover in a cleaning product and use it to clean the inside walls. You can rinse the roller off and repeat the previous process as many times as you want.

4- Leaky Pipes

Leaky pipes are easy to detect because they cause shower drain odors like sewage or rotten eggs. This is mainly because they allow sewer gases that consist of hydrogen sulfide to escape to your bathroom.


Drainage pipes’ main function is to keep the sewer gases contained. When they malfunction, they leak the gas through your shower drain. You may be wondering what causes leaks in your pipes. They’re mainly caused by pipes’ perforation and loose fittings.

In the case of loose fittings, the culprit is probably a poor installation. Consequently, this problem may damage your PVC piping.

Among the common possible causes of leaky pipes are clogs. For example, if your shower drain is clogged with a substance that contains a cleaning product, it may eat through the pipes and cause perforations. This is especially common if the pipes’ walls are suffering from corrosion.


Unfortunately, fixing this issue isn’t as easy as the previous solutions we’ve discussed. You may need professional help to detect the exact issue. Also, it depends on the material your pipes are made of and many other factors.

For example, if your pipes are made of cast iron, you might need to replace them. This can only be done by licensed plumbers, so don’t waste time trying to fix it on your own.

How to Detect the Culprit

Homeowners can easily detect the specific issue that’s causing the shower drain smell. You don’t have to contact a professional unless you’ve tried all the home remedies available.

Like we’ve mentioned before, different problems cause different odors. You can identify the culprit by the smell it caused in your bathroom. For instance, if your shower smells like rotten eggs, you’re probably dealing with leaky pipes. On the other hand, a sewer gas smell indicates a malfunctioning P-trap.

Finally, musty smells are proof that you have mold and bacterial waste growing inside your shower drain.

How to Prevent Shower Drain Smell

Install Mesh Drain Screens

To avoid dealing with a drain clog, you can reduce the amount of soap scum and hair that goes through it. This can be easily done by installing a hair catcher under the drain cover, also known as a mesh screen. It works by catching debris and hair during your shower. Moreover, you’ll only need to empty it a few times a month.

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Flush the Drain Regularly

Close up detail of unidentifiable yellow rubber gloved hand spraying water around floor drain for shower stall

Unfortunately, hair catchers only block debris from going into the drain. They won’t block body oils from going through, so you have to flush your drain regularly. You can do so by pouring one cup of boiling water down the shower drain every week. Doing this regular maintenance will keep your pipes free of grime and gunk.

To Wrap Up

Most homeowners don’t know how to deal with bad shower drain odors in their bathrooms. In addition, they cause discomfort and embarrassment, especially if they’ve appeared in a guest bathroom. Fortunately, they’re mostly easy to fix. 

If you suspect that a drain clog is causing your bathroom’s stench, you can easily clear it using boiling water or a drain snake. But suppose that you notice a biofilm buildup – in that case, you should clean it as soon as possible using antimicrobial disinfectants.

Yet, in case you’ve tried everything, and your nose still detects the foul odors, you can contact a professional plumber to come to your home and check your system. We hope you’ve had enough information about shower drain smells now!

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