Why Does My Shower Drain Smell?

Showering should be a pleasant experience that leaves you feeling fresh, so shower drain odours are the last thing you need. Often caused by issues such as blockages, bacterial growth or deeper drainage problems, it may not always be something you can solve with DIY steps.

If you have a persistent shower drain smell, it could indicate the need for a professional drainage survey. That’s where we come in at Express Drainage Surveys, where our team are specialists in identifying the root cause of deeper drain smells using advanced diagnostic technology. This month, we’re going to take you through all aspects of a smelly shower drain, including the causes, how to diagnose it, when it might need more serious inspection and tips on how a drainage survey could be the start of a solution.

What causes a shower drain to smell?

There are so many things that can create a bad smell from your shower drain, so to help you narrow down the issue, we’ve highlighted some of the most common causes.

Blockages in the waste pipe: Hair accumulation, soap scum and hard water deposits are quite common, but they trap stagnant water and make drainage slow. You’ll probably notice the smells get stronger after using the shower.
Problems in the main waste line: In some severe cases, the smell can be caused by issues with your waste drainage line. This could be a result of collapsed pipes, tree root intrusion or some other damage contributing to a blockage, but you’ll likely notice the smell coming from more than just one drain.
A dry or faulty P-trap: The P-trap is simply the bend in your pipe, and it’s designed to block smells coming up from your drainage system. If this becomes dried out or if you use the shower infrequently, it can let bad odours into your home through the shower drain.
Biofilm buildup: Whether it’s soap scum, oils or skin cells, the biofilm collecting in your drain is a sticky residue. The warm, damp environment accelerates bacterial growth and can result in a musky, stagnant smell.
Mould or mildew in the drain: Trapped moisture in your drain, combined with poor ventilation in the room, can create a musty, earthy smell if left to build up over time.

How to diagnose the cause of shower drain smells

With so many different causes, how can you tell what the real cause of the drain smell is? We have a quick step-by-step guide to help you check:

Start by checking if the trap is dry – run the water in your shower for 10 seconds.
Next, remove the drain cover and check if there is any visible debris.
Make a mental note of whether you can smell the odour constantly or whether it just appears after you’ve run the water.
While you’re running the water, test the flow speed, as slow drainage points to a blockage.
Inspect the shower itself for any signs of leaking around or below (this may not be possible if your shower doesn’t have an accessible side or tray).

The above steps can help you investigate and match the signs you see to the potential causes. However, since odours can originate from deeper in your system, the faults may not always be visible. Only a professional drainage survey can detect cracked pipes or hidden structural damage further in your external waste pipes.

DIY solutions to reduce or eliminate shower drain smells

While we don’t actually recommend DIY solutions for eliminating drain odours if you don’t know what the cause is, there are some very simple steps you can take before seeking the services of a professional:

Clean the drain cover and surroundings. General upkeep and removing debris, soap and hair can help to reduce the amount of bacteria in your shower drain.
Using flushes of boiling water for a deep clean. This is safe for most shower systems, but always check first. Hot water can help to remove any biofilm lingering in your pipe.
Improve ventilation. Run your extractor fan or open a window to help reduce humidity in the room overall and prevent mould or mildew in your drains.
Keep the water flowing to prevent traps from drying out. The water doesn’t have to be on constantly, but simply running any unused shower once a week can keep the system performing as it should.
Avoid chemical drain cleaners. This is because UK pipework may not be able to withstand the strong chemicals in certain products. It’s also harmful to the environment if you consistently use harsh chemical cleaners.

When to call a professional: Signs that the problem is serious

Many people will attempt to struggle on when bad shower odours first occur, but there are certain scenarios where it’s vital that you call in the professionals, including:

When you have persistent shower drain odours despite a good, regular cleaning schedule.
When you have repeated blockages that suggest an underlying issue is at fault.
When you notice water stains, damp patches or mould, it indicates a leak.
When there are smells coming from multiple drains, pointing to an external drainage issue.
When you hear gurgling sounds from your shower drain, suggesting air pressure issues.

How a professional drainage survey helps identify the root cause

At Express Drainage Surveys, while we can’t clean your shower for you, we can certainly help get to the bottom of any external drainage issues that may be contributing to a bad shower drain smell.
We use CCTV camera technology to pinpoint exactly where the issues are in your drains before making expert recommendations on the action to take. We’ll identify blockages, leak locations, structural faults and much more. You can find out more about this and other drainage services we offer via the following pages:

Don’t ignore persistent odours – talk to our team today if you suspect there is an issue with your outside drain and we’ll ensure you get an accurate diagnosis for total peace of mind.