Share:
Are you experiencing unpleasant odours coming from your shower drain? Don't worry, you're not alone. Our bathrooms should be a peaceful, spa-like escape. Yet, if you've noticed a foul smell coming from your shower drain, that may not be the case.
Shower drain smells are a common problem faced by many homeowners, yet in most cases, there can be a simple explanation that can be solved by DIY measures. 
Here, The Bathroom Showroom has created a quick guide to help you find the culprit of your shower drain smells, so you can get your bathroom back to looking, and indeed, smelling fresh!

Why Your Shower Trap Smells – And How to Solve It

  • Problem With the P-Trap
One of the most common issues is a problem with the P-trap. You may find that if your bathroom smells like a sewer after a shower the P-trap is the culprit. If you can look underneath your shower drain, you'll see a U-shaped pipe that the water passes through. This is the P-trap. The purpose is to hold a small amount of water at all times to block sewage gases from coming back up the pipe and into your bathroom.
If you haven't used your shower in a while, it's possible the water has evaporated. Simply run water in the shower for a few minutes and the P-trap will refill. You can also mix water with a touch of ZoFlora to add a pleasant aroma, perfect for guest bathrooms.
However, if you have used your shower recently, it could be a sign there's a leak in the P-trap. In this case, the pipe needs to be replaced. This will help resolve the smell and prevent further water damage in your home.
  • Build-up Of Biofilm
Biofilm is a thin, slimy layer of bacteria that can grow from all the water, soap, shampoos, and body oils that go down the drain. This can then accumulate inside the pipes, causing your shower drain to smell like rotten eggs.
To get rid of the odour, and the build-u, you can mix 1 part bleach with 1 part water and pour it down the drain. Alternatively, you can pour 1 cup of baking soda down the drain, followed by one cup of white wine vinegar. Cover the drain as the mixture fizzes, then flush with hot water.
If hair gets stuck in the drain or pipes, it can make the biofilm even worse. Adding a hair trap can help stop the build-up of biofilm.
  • Mould
If your shower drain smells musty, you may have mould growing underneath your drain cover. Feel the drain cover to see if it's loose. If your drain cover isn't perfectly sealed, that small wet space will be the perfect breeding ground for mould.
Before sealing it, you'll need to remove the cover and clean the area thoroughly. Using a mould spray and following the instructions will help clear the mould and the smell. If it's really bad, you may need to scrub the cover too. If this doesn’t solve the issue, you may need to buy a new drain cover.
  • Leaky pipes
If water is draining away okay and you've checked to make sure the pipes aren't clogged with hair or biofilm but your shower drain still smells, it may be that you have leaky pipes. Leaky pipes in your bathroom walls or under the shower will allow sewer gases, like hydrogen sulphide, to escape causing your shower drain to smell like rotten eggs.
Drainage pipes are designed to keep sewer gases contained, and if it's not coming from the P-trap then you may have a leak somewhere in your drain line.
Leaks are caused by either perforations in the pipes or by loose fittings between pipe joints. Often leaky pipes occur over time due to corrosion. Fixing a leaky pipe is best left to the professionals, so calling in a plumber is a must. A plumber should be able to fix the issue, so you can go back to breathing easy in your bathroom.

Frequently Asked Questions About Shower Drain Smells

What Types of Smells Indicate Specific Problems?
  • Rotten egg/sulfur smell: Often points to a dry P-trap, sewer gas infiltration, or bacterial growth producing hydrogen sulfide gas.
  • Musty/mildewy smell: Typically indicates mould growth, biofilm buildup, or stagnant water from a clog.
  • General foul/sewage smell: This can be a severe clog, a dirty P-trap, or, in more serious cases, a leaky drainpipe or sewer line issue.
How Can I Prevent Shower Drain Smells?
Prevention is key:
  • Regular Cleaning: Make it a habit to regularly clean your shower drain. This includes removing hair and visible debris from the drain cover after each shower.
  • Drain Screens/Hair Catchers: Install a drain strainer or hair catcher over your shower drain to prevent hair and larger debris from going down the pipe. Remember to regularly empty and clean it.
  • Regular Flushing: Periodically flush your drain with hot (not boiling) water or baking soda/vinegar mixture to prevent buildup.
  • Maintain P-Trap: If you have a guest bathroom or a shower that's rarely used, run the water for a minute or two once every couple of weeks to keep the P-Trap full.
  • Good Ventilation: Use your bathroom exhaust fan during and after showers to reduce moisture buildup, which helps prevent mould and mildew.
  • Avoid Pouring Grease: Never pour grease or oil down any drain, as it can solidify and cause clogs.
  • Use Liquid Products: Some bar soaps can contribute more to soap scum buildup than liquid soaps and shower gels.
When Should I Call a Professional Plumber?
It's time to call a professional if:
  • The odour persists despite your cleaning efforts.
  • The smell is particularly strong or foul, especially if it smells like raw sewage. This could indicate a serious sewer line issue or a broken/clogged vent.
  • You suspect a leaky pipe or visible damage to your plumbing system.
  • Clogs are recurring or you have a complete blockage that DIY methods can't clear.
  • You're unsure of the cause of the smell and want a definitive diagnosis.
  • You notice other issues like slow drainage, standing water, or unusually high water bills in conjunction with the smell.
A plumber can use specialised tools like cameras to inspect your pipes, identify the root cause of the problem, and provide a lasting solution, whether it's a deep cleaning, pipe repair, or addressing vent line issues.

Is It Time to Consider a New Bathroom Suite?

If your bathroom woes extend beyond the shower drain smells, it might be time for a complete makeover. You can easily make your bathroom the most important room in the house with our help. Whether you're looking to create a sleek and stylish space or your style is more traditional, we have a bathroom suite for you.
If you’re considering adding a new shower or new bathroom suite book an appointment with The Bathroom Showroom. Experts in all things bathrooms, we can help turn your dream bathroom into a reality.