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6 Reasons Why Your Shower Drain May Smell According to Plumbing Pros

Expert tips for banishing bad odors from your bathroom shower drain. 

Taking a shower should be a spa-like and relaxing experience. But when you jump in only to have your nose assaulted by an awful stench, any chance of relaxation goes right down the, well, drain. And while a smelly shower drain is just gross, the good news is that most of the causes are easily remedied. Read on to find out what might be causing your shower drain to smell along with ways to fix the problem — and how to know when it’s time to call in the pros.

6 reasons you might have a smelly shower drain

1. The drain is clogged

If anyone in your home has long hair, it’s a good bet that a clogged drain is caused by the hair we all naturally lose in the shower. And any hair that makes its way down the drain provides the perfect environment for rinsed out conditioner and soap to cling to. “Almost everything we wash down the drain is made up of organic material, which breaks down over time, and this causes odor,” says Nicholas Clark of Norfleet Family Plumbing in Mesa, AZ.

Related: Plumbers Weigh In: The Best Way To Remove Smells From a Kitchen Drain + How To Unclog a Slow-Draining One

The easy fix

To prevent both drain clogs and the odor that accompanies organic material breaking down, Clark recommends clearing the drain of hair build up on a regular basis. “Using a zip stick/strip weekly to remove hair build up is an easy and cost effective way to stop issues from occurring,” he says. And if your shower backed up because of the drain, be sure to disinfect after taking care of the clog. 

See the folks at Budget Heating, Cooling, & Plumbing put a Zip It drain cleaner to use in this video:

Related: These Kitchen Staples Will Unclog a Bathtub Drain Quickly Without Harsh Chemicals

2. Smelly shower drain reason: Biofilm

Biofilm is the slimy stuff that comes up along with any hair you remove from the shower drain. It tends to smell a bit like rotten eggs and is essentially a collection of bacteria that grows on the sticky remainders of soaps and shampoos. It’s even been associated with Legionnaires Disease and other health issues! If you haven’t cleaned your drain in some time or a clog sat around for a bit, it’s likely that just using a zip stick to remove hair will be enough to get rid of any bad odors. The drain will also need to be cleaned in order to remove the bacteria-filled biofilm that may have formed there.

The easy fix

There are several ways to get rid of biofilm and have your shower drain smelling great again. “Only dumping in soap or drain cleaner probably will not suffice. Just like you rub your hands together while washing them (as opposed to just pouring soapy water over them ) scrubbing the sides of the drain down tube and p-trap is really the long term solution,” says DIY expert Dave of HouseBarons.

He recommends using a stiffer bristle brush with a long flexible shaft, and says, ”The better job you do cleaning the drain tube and p-trap, the less often it will need to be done.” You can use an enzymatic cleaner like Green Gobler Enzymatic Drain & Grease Trap Cleaner before cleaning or you can use a DIY cleaner of one cup baking soda followed by one cup vinegar. Let the cleaner work for 10 minutes or so, and then get to work scrubbing. 

See HouseBarons clean a smelly drain with a bristle brush in this video:

3. Your P-trap is dry

A smell like sewage coming from your shower drain could be an indication of a dry P-trap. The P-trap is the curved loop below the drain in your sink, tub, toilet or shower. The loop in the trap fills with water, which keeps gases from the sewer or septic out. If this loop dries out, those gases will seep into the drain and make their way up, causing the sewage odor. This can happen if you aren’t using the shower on a regular basis, especially in the summer when it’s hot and water can evaporate quickly.

The easy fix

“Use the shower often especially during hot months to ensure a proper P-trap seal,” says Clark. If it’s a second bathroom that doesn’t get a lot of use, pouring a cup or so of water into the drain at least every month or so will keep the trap filled with water and prevent any sewage smell from leaking out. If neither of these things works to banish the odor, though, you’ll likely want to call in a plumber as the cause could be a larger plumbing issue. 

4. Smelly shower drain reason: A dirty P-Trap is causing a smelly shower drain

If hair and other dirt and debris make it past the drain and into your shower’s P-trap, it can become clogged as well, leading to the same rotten egg smell a clogged drain can have. Unfortunately, a dirty P-trap is a bit harder to access than just a dirty or clogged drain.

The easy fix

If cleaning just the drain hasn’t worked, you may have to disassemble the P-trap and clean that. “That’s a little hard core though,” says Dave of HouseBarons, especially if you don’t have easy access. If you’re access is limited and you’re unsure of the steps, this may be another job for a professional plumber.

See this video from Service Champions Plumbing, Heating & AC on how to clean a dirty P-trap:

5. Your drain is moldy

A musty-smelling shower drain can be an indication of mold growing beneath the drain cover. Mold is a fungal growth that grows and spreads on all kinds of damp surfaces — and it can be hazardous to your health if it’s inhaled. The good news is it’s easily remedied.

The easy fix

Use a screwdriver to remove the shower drain cover, and soak it for a few minutes in a mixture of one part bleach and four parts hot water, which instantly kills mold. Wipe the moldy remnants away, and replace the drain cover.

The video below shows you how to remove a shower drain that doesn’t have screws:

6. Smelly shower drain reason: Leaking drain pipe or a clogged went pipe

If you’ve looked into and cleaned up all of the above issues and you’re still smelling sewage, rotten eggs, or mold coming from your drain, this could potentially be an indication of a large piping issue, such as a leaky drain pipe. A leaky pipe would prevent wastewater from leaving the drain, allowing it to leak into the surrounding area beneath your tub or shower, say the folks at Benjamin Franklin Plumbing. A sewage smell that won’t go away could indicate a clogged vent pipe.

The easy fix

Since leaky pipes can lead to both odors and cause damage to your home, you’ll want to call in a pro to identify and fix the problem. If you have access to the vent pipe, you may be able to fix a clog by running water through the vent pipe, but it’s a bit involved and unless you’re a super handy DIYer, it’s also best left to an expert. A plumber will do a smoke test, which is an effective way to identify any potential cracks or compromised elements of the vent system, says Clark.

See this DIY video on how to flush a clog out of a plumbing vent pipe:

For more on fixing issues in your bathroom, click through the links below!

Experts Caution Against Using Baking Soda and Bleach for Mold — The $2 Toilet Bowl Cleaner To Use Instead

Getting Rid of Mystery Stains in Your Toilet Bowl Is Easier Thank You Think — Here’s How

How to Clean a Bathtub Without Breaking Your Back: These Kitchen Staples Will Get It Sparkling

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