In this article, we run through how to get rid of smelly drains in your bathroom, some of the common causes, and how to prevent them from happening again. 

DCM Plumbing is the best plumber on the Gold Coast. We are available 24/7 for all your plumbing needs. With over 900 5* Google reviews and 35 years of experience, we are known as the best for a reason. Got a blocked drain? Need help with leak detection? Want to learn how to clear a blocked drainWe can help.

What causes smelly bathroom drains?

There are a variety of causes of smelly bathroom drains. 

Build-up of dirt, hair, and other organic material

Whilst modern plumbing is truly a feat of engineering, it’s not perfect. Built-up dirt, hair, and other organic material can create unpleasant smells. This is because bacteria release foul odours as they thrive on the spoiling material. 


Mould is a type of fungus that is usually harmless (and even makes cheese taste good); however, it loves moist places and can produce nasty smells once it really starts growing. They release puffs of gas that smell and can also induce headaches and respiratory problems. Be sure to contact us immediately if you suspect mould growing in your bathroom drains, as it can become a significant issue if not taken care of early. 

Old, weakened pipes

Old pipes start to weaken and crack over time, which can cause leakages and, from there, buildups of bacteria and mould. So it’s best to check your pipes and ensure they are in good condition – regular plumbing maintenance can save you from disaster in the long run. 

Faulty trap

What Causes Smelly Bathroom Drains

A trap is an ingenious piece of plumbing that stops sewer gas from entering your home. They work by always keeping some water in the piping, which acts as a seal against sewer gas, as you can see in the image above. Unfortunately, if a trap stops working as it should or dries out, this means that sewer gas can enter directly into your home, causing quite the stink!

Malfunctioning vent pipe

On top of some traps, a poorly functioning vent pipe can cause bad smells in your bathroom. These sit on your roof and help regulate air pressure in your pipes, allowing waste and water to move through the drains without any vacuums developing that might slow down drainage. They also allow for the escape of sewer gas from the pipes, so when not working as they should, they can cause some funky smells in your home. 

Blocked sewer line

A blocked sewer line is a common cause of stinky bathroom drains. It can cause a back-up and build-up of sewerage from reaching the council sewer system, leading to stagnant sewerage, which inevitably leads to foul-smelling drains.

How to fix smelly drains

There are a number of ways to fix a smelly drain, and if you’re unsure of what to do, contact us today. We can identify and treat any stinky bathroom drains and make sure they’re not likely to happen again. That being said, there are some things you can try beforehand:

1. Find the cause of the smell

The first step in treating stinky bathroom drains is locating the source and identifying the smell’s cause. 

2. Pour ½ cup of baking soda down the sink, followed by 1 cup of white vinegar

This causes a chemical reaction that can loosen any debris as well as neutralise some of the odour. Let the mixture sit for at least a few minutes.

3. Pour boiling water down the drain

Pour a kettle full of boiling water down the drain after the baking soda and vinegar mixture has loosened up any buildup. This can help wash away any gunk and make your drains smell as good as new. 

If this method doesn’t fix your smelly drain, there are some further alternatives to try:

Use a plunger

If hot water and vinegar can’t eliminate the smell, there may be a more substantial blockage. A plunger can help loosen any debris and be combined with the above method. Repeat until the smell is gone. 

Try a drain snake or coat hanger

This takes fixing a blocked drain back to basics – if hot water, baking soda, and a plunger don’t work, then maybe a bit of brute force can help eliminate the problem! 

How to stop smelly drains

The best way to stop smelly drains is through prevention. Here are a few simple guidelines you can follow to reduce the likelihood of smelly drains in the future:

  • Avoid letting too much hair go down the drain
  • Use any taps in your home regularly as this keeps the traps hydrated and functioning properly
  • Undertake regular plumbing maintenance from a licensed professional
  • Pour boiling water and/or a vinegar and baking soda solution down your drains regularly

What do professional plumbers use to unclog drains?

The way we unclocg most bathroom drains is by scooping out anything inside the drain, and then pouring in commercial grade acid to dissolve any leftover debris. After this, we put a GrateMate in the floor waste which looks like an upside down plunger and sits in the water trap. This prevents smells from coming out of the pipework into the bathroom – for good. 

Need help fixing your stinky bathroom drain?

Sometimes home remedies just don’t cut it when trying to fix a stinky bathroom drain, and you have to admit defeat and call a professional plumber.

At DCM Plumbing, our Gold Coast plumbers are fully qualified, insured and ready to respond to all of your plumbing needs. We have extensive knowledge and experience within the industry and can get to you fast, so if you need help with a stinky bathroom drain, contact us today.