A bad smell coming from the shower drain can have a number of causes. Identifying the cause is the first step of treatment, so keep reading for possible reasons why your shower drain smells:

Clogs

Clogs are a common cause of unpleasant shower drain odor. Hair, soap scum, and grime can build up inside the drain and attract bacteria, leading to a blocked and smelly shower. Slow-draining water that collects at the base of the shower is typically an indication that there’s a clog in your shower drain.

Biofilm or mold buildup

Have you noticed a mildewy odor in your drain, or does your bathroom smell musty after a shower? If so, there may be mold or biofilm (slimy bacterial waste) growing inside your shower drain. ‘Pink mold’ is a common biofilm that develops in bathrooms. It’s not actually a mold, but an orangey pinkish film containing the bacteria S. marcescens. This can grow on bathroom tiles as well as in and around the drain, so if you’re seeing a lot of it - chances are you’ve found the source of that nasty shower drain smell.

P-trap problems

If your shower drain smells like rotten eggs, this indicates either bacterial growth or a problem with the P-trap. The U-shaped P-trap pipe can dry up, allowing sewer gases to escape into the bathroom. Typically, this problem arises in underused showers. If you can’t see water when you shine a flashlight down the drain, this is likely the culprit. If there is water, this indicates a different problem.

Damaged pipes

Sometimes, the sewer smell in your shower is due to faulty drainage pipes. Punctured, corroded, or loose pipes can leak and release sewer gases. This can be a serious issue and may require a professional rather than a DIY approach. You should seek help immediately if you start to smell sewer gas, as this can be toxic if left to accumulate.

Once you’ve identified what’s causing your stinky shower drain, the next step is to fix it. In most cases, cleaning the drain properly to remove dirt, grime, and buildup is the best way to get rid of shower drain smells. Here’s what else you can do:

Clear the drain

If you suspect that a clog is causing your shower drain odor, first try removing buildup at the opening of the drain. To do this, take off the drain cover (they are usually loose or detachable with a screwdriver). Remove any clumps of hair or soap scum that may be attached to the drain cover.

Next, you can move to unclogging the shower drainpipe. There are many techniques you can use to unclog your shower, including using a plunger or a drain snake, trying home remedies, or using a drain cleaning product such as Drano^® Max Gel Clog Remover or Drano^® Hair Buster Gel. Check out our How to Fix a Clogged Shower Drain blog post for a step-by-step guide on using these methods.

Sanitize and deodorize the shower drain

A foul or musty smell coming from shower drain can be unpleasant. You can address this problem by killing the mold and bacteria lurking in the pipe.

If there’s mold on the drain cover, clean it thoroughly using a mildew remover product or household cleaner. You should also clean any visible buildup on the shower tiles or door. Next, tackle the biofilm and mold in the drain.

Here’s how to clean a smelly shower drain:

1. Clean the drain cover.
2. Using a tool such as a brush or old toothbrush, scrape the inside of the drain to dislodge any biofilm sticking to the drain walls.
3. Pour an antimicrobial disinfectant into the drain. You can use a ½ cup of bleach or make your own drain cleaner from ½ cup vinegar and ½ cup baking soda. (Do not use vinegar and bleach together as they create a highly toxic substance!)
4. Let the product work for about 1 hour.
5. Flush the drain with a few cups of hot or boiling water. Note: do not use boiling water on PVC pipes as this could damage them.

If you have a spare paint roller lying around the house, you could also try this shower drain deodorizer method:

1. Remove and clean the drain cover.
2. Dip a paint roller cover into bleach or other cleaning product, then push the roller into the drain.
3. Rotate the roller and gently scrape the drain walls to clean their surfaces, periodically rinsing with water.
4. Repeat this until the biofilm residue is no longer visible.

Inspect your P-trap

A dry or dirty P-trap can also cause a smelly shower drain. If your P-trap is dry, try pouring 2 cups of water into the drain. Wait for 1 hour, then check if the water is still there. If not, you may have a cracked or broken P-trap which requires the attention of a plumber.

If the shower doesn’t get used often, you can try pouring 4 ounces of cooking oil into the drain. This may slow the evaporation of the water to ensure the P-trap doesn’t dry out, preventing sewer gases from escaping.

Call the plumber for deeper pipe problems

Finally, if you can’t determine the source of the shower drain odor, or if these remedies haven’t worked, it may be time to call a professional. There might be a problem with a drainage pipe or P-trap that is too complex for a quick DIY repair.

It’s especially important to get a plumber’s help when there’s a sewer smell in the shower or bathroom. Sewer gases can be toxic in large quantities.

Prevention is often the best cure - and this is certainly true when it comes to shower drain maintenance and avoiding nasty drain stenches.

Here are Drano’s top tips on preventing a stinky shower drain:

• Buy a hair catcher to deter hair clogs forming in the drain.
• Regularly clean the drain cover.
• Periodically flush non-PVC pipes with hot water to remove soap scum or bacteria buildup.
• Run water into underused showers occasionally.
• Use an enzyme based drain cleaner such as Drano^® Max Build-Up Remover on a monthly basis to prevent clogs from forming and to help keep your shower smelling fresh.

Soon all your smelly shower troubles will be down the drain. To feel inspired by more household tips, tricks, and solutions to all your drain problems, visit the Drano^® Clog Basics blog.

Browse the full range of Drano® products here.