smelly drain

How to Clean a Smelly Drain in 6 Easy Steps

One of the worst odours you are likely to ever encounter at home is that of a smelly drain. It’s unpleasant, overpowering and tends to stick around.

However, there’s no smoke without fire, and the only way to clean smelly drains is by attacking them at their source. Learn why smelly drains happen in the first place, how to prevent it and how to clean a smelly drain within!

What Are Common Causes of a Smelly Drain?

There are many possible reasons why drains would start to smell. These include:

Trapped Gunk or Dirt:

Kitchen and bathroom sinks are prone to developing bad odours, primarily because of hair, food, soap particles, grease and other types of gunk that accumulate and attract bacteria, which then emit a foul smell.

Mould Growth:

If you smell a musty odour, it’s highly likely that it’s coming from a mould source. Mould is naturally attracted to moisture, so it’s not uncommon to find them thriving in drains and releasing tiny puffs of gas which smell.

Dry or Empty P-Trap:

If you’re unfamiliar with the p-trap, all you need to do is look under your sink and find the curved section the drainpipe. Its primary function is to capture water to form a plug against sewer gases that are coming back up the pipe. This is why a dry and empty sink that hasn’t been used in a while can start to smell.

Clogged Vent Pipes:

Aside from the p-trap, venting pipes are also used to prevent sewer gas from entering households. Venting pipes get rid of back-flowing sewer gases and push these up to the rooftop. However, when these get clogged with debris, it can lead to water pooling in the sink which can result in stagnant odours. Clogs will also force the sewer gases back down and up through your drains.

Water Issues:

If you detect a rotten egg smell, it may be caused by the reaction produced when sulphate-reducing bacteria mix with the sulphates in a water heater.

Plumbing Problems:

Structural problems such as water leaks, rotting drain pipes, aged pipes and missing traps or vents can all cause odours to seep from a sink.

Tree Roots:

If a young tree is planted too close to your house, there’s a chance for tree roots to grow and penetrate your plumbing system. This can lead to blocked pipes and smelly drains.

Sewer Line Issues:

If there is a break or block in the sewer line carrying wastewater away from your household out to the municipal sewer system, expect bad odours, as well as gurgling sounds and clogs in the drain.


Once you’ve identified the cause of the smell, you can start assembling your supplies to clean your smelly drain. Remember that the supplies remain the same, whether it’s smelly bathroom drains or kitchen drain smells that you’re dealing with.

Checklist of Materials Needed

To get you started on your drain-smell-cleaning quest, make sure you have the following materials:

  • Rubber gloves
  • Hot water
  • Vinegar
  • Baking soda
  • Petroleum jelly
  • Bucket
  • Hose
  • Plunger
  • Wrench
  • Snake hose auger or metal hanger

With all of these items on hand, you’re now ready to tackle your smelly drain problem.

How to Clean a Smelly Drain

As the checklist of supply shows, there are various materials you can use to get rid of any foul smell coming from your drains. However, the best way to approach the problem is by beginning with the simplest solution. If it doesn’t work, move on to the next.

Check out the following steps:

1. Identify the Source

Is the smell coming from your bathroom or kitchen sink? How about the shower drain? Knowing the source of the foul smell will help you to refine your approach on how to get rid of smelly drains.

2. Hot Water or Vinegar

To start, bring water or white vinegar to simmering point (when tiny bubbles appear). Pour half the amount down the drain slowly.

After a few minutes, pour in cold water so any remaining gunk solidifies, and then pour in the leftover hot water or vinegar to wash away the rest of the gunk.

If you have PVC pipes be careful of pouring boiling water down the drain – it has the potential to cause pipe damage!

3. Use a Plunger

You can try using your plunger to unclog your shower drain. But first, apply some petroleum jelly on the edge of the plunger as this will help provide a better seal. Position the plunger over the drain cover.

Fill the shower with hot water just enough to submerge the end of the plunger, and then start plunging vigorously until the clogged drain is no more.

4. Combine Baking Soda & Vinegar

Let the tap run for a few seconds and then turn it off. Pour a cup of baking soda into the drain, and follow it up with two cups of hot vinegar (near boiling point). Allow the mixture to fizz and leave for an hour. Pour hot tap water down the drain and see if the clog clears.

5. Use a Snake Hose Auger or Coat Hanger

You can try using a snake hose auger or drain snake, which comprises a flexible metal tube fitted into a plastic tube with an auger. Insert the auger into the clogged drain.

Hold the plastic tube tightly and, as you force the flexible tube into the drain, turn the handle on the other end of the flexible tube. This should clear out the clog. If this method works, make sure you sanitise the snake hose before putting it back in storage.

If you don’t have a drain snake, you can improvise using a metal wire coat hanger or any piece of wire. Create a hook at the other end of the wire and slowly slide it down the drain until you reach the clog. Gradually pull the wire out.

If this attempt is productive, you’ll usually find a clump of hair and gunk attached to the hook, so make sure to give your makeshift drain hook a good cleaning, as well as the bathroom.

6. Clean the P-Trap

Protect your hands with rubber gloves. Using a wrench, disconnect the curved section of the plumbing underneath the sink. Get rid of gunk and water left in the trap and keep these in a bucket. Rinse out the p-trap outside using a garden hose.

Once the p-trap is clean, reattach it securely to the plumbing system, and then try using the sink.


If the problem is a clogged drain vent, remove any trapped debris. However, if you don’t have the proper safety gear, it’s best to seek professional help. The same goes for sewer line problems which can only be resolved by plumbing experts.

How to Prevent Smelly Drains From Happening

You can avoid having to deal with the problem of how to clean smelly drains by preventing them from happening in the first place.

  • Never dispose of fat, grease and oil in the sink.
  • Bin all food scraps or put them in your compost heap.
  • Pour boiling water into all household drains weekly.
  • Implement the baking soda, vinegar, and boiling water step (no. 4) monthly.
  • Keep your garbage disposal clean.
  • Use your taps regularly to prevent drying out the p-trap.

Do You Still Have a Smelly Drain?

Smelly drains are an unpleasant household problem that you can try resolving on your own.

Depending on the root cause, finding out what will work depends a lot on trying a few simple solutions. 

However, when all else fails, make sure to call in the professionals. Tunnel Vision has the tools and the skills to clean any smelly drain quickly and with minimal convenience to you. Call us on 1800 631 799 or book online today!

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