Why Your Washing Machine Makes Your Kitchen Sink Smell (and how to fix it)

Have you ever noticed your sink smells when the washing machine is on? Several factors, including blocked pipes and improper venting, can cause this smell.

By identifying the underlying issues and applying simple solutions, you can get rid of the smell completely. 

In this article we’ll look into what causes that bad smell in your washing machine and your kitchen sink and what you can do about it. Keep reading to discover practical tips for maintaining a fresher, odour-free kitchen and laundry area.

What Makes The Washing Machine And Kitchen Sink Smell?

Probable CauseSolution
Blocked or Partially Blocked Waste PipeRemove the U-bend and clean out any accumulated kitchen waste
Washing Machine Waste Pipe IssuesEnsure the washing machine’s waste pipe is not pushed too far in, which can cause blockages
Poor Vent System InstallationFor improperly installed vents, seeking professional help to correct the setup ensures that it properly vents out sewage gases
Drains Have A Partial BlockageCheck the drain that serves the kitchen and see if there is anything partially blocking it. Remove any blockages if you can, or call in a plumber to sort it for you

If your kitchen sink smells, it may be caused by sewage gas not venting properly, signalling a potential plumbing problem. 

Besides plumbing issues, long-term exposure with sewage gas, which includes toxic compounds such as ammonia, carbon dioxide, and hydrogen sulphide, can lead to health problems including nausea, headaches, fatigue, and memory issues.

The reality is, the smell is just an indicator that something else is going on. If the kitchen sink is smelling after the washing has finished, and it doesn’t smell like washing detergent or fabric softener, you’ll need to investigate. Typically, the cause can be traced back to one of these issues:

Blocked Or Partially Blocked Waste Pipe

kitchen sink

In most kitchens, washing machines share the waste pipe with the kitchen sink, meaning water from the machine must go down the same pipe as that from the sink.

Under your sink, there should be a U-bend which is designed to prevent any smells from the drain getting into the kitchen via the sink drain (plug hole). 

Over time, this U-bend can become partially blocked with kitchen waste which rots down and begins to smell.

As the washing machine waste water runs lower down through the same pipe, it can cause air to flow upwards. This will force any smelly air upwards towards your kitchen. To fix it, simply remove the U-bend and clean any kitchen waste.

The Washing Machine’s Waste Pipe Can Cause The Blockage

If the washing machine’s waste pipe is pushed in too far it can block your sink’s waste pipe and cause bad odours. 

To fix this, make sure the washing machine’s waste pipe is installed correctly. Ideally, the machine should have its own separate waste standpipe, including a U-bend for easy cleaning and independent operation from the sink.

Poor Vent System Installation

Proper installation of a vent system is key to getting rid of foul odours. Should the vent become blocked, it can cause the smell to linger and trap it within the house. 

To fix this, make sure to clean out your vent by removing any blockages. It’s advisable to seek expert help to ensure the installation is corrected, allowing it to vent sewage gases efficiently and keep your home odour-free.

The Drains Have A Partial Blockage

Sometimes, the kitchen sink’s drain can get partially blocked. Normally, this wouldn’t be a problem as the drain doesn’t see much use and doesn’t cause any odour. Connecting a washing machine to the same drain increases the overall use, which can then cause foul smells in your kitchen sink.

Check the drain that serves the kitchen and see if there is anything partially blocking it. Remove any blockages if you can, or call in a plumber to sort it for you.

Can The Washing Machine Cause The Foul Smell In The Kitchen?

Washing Machine

Often, the problem lies with the washing machine rather than the waste pipe. With time, the washing machine can develop various issues that lead to odours spreading into the kitchen or any room it’s located in.

It could be that the problem is;

  • The machine’s waste pipe is blocked or partially blocked
    If the washing machine has a blockage or partial blockage in its waste pipe, it could create a foul smell in the machine itself and in the room it is situated in – the kitchen.
  • A buildup of bacteria or mould
    If you always run eco washes which run at low temperatures, your machine is likely to get a buildup of mould and bacteria which can produce foul smells. This is often more prevalent in areas of hard water because the limescale deposits provide a surface for the bacteria to breed on.
  • The machine is in need of a service wash
    Using an eco wash setting on your washing machine may lead to mould and bacteria buildup if not cleaned regularly at high temperatures, which are necessary to kill bacteria effectively. This also leads to detergent scum and residue. To avoid this, manufacturers recommend a monthly service wash. If there’s no service wash option, select the highest temperature cycle. Do this without any laundry, using either a commercial cleaner or natural alternatives such as white vinegar, bicarbonate of soda, or soda crystals.
  • The machine is lacking regular maintenance
    If your washing machine smells like sewage, the cause might be dampness, not sewer gas. Bacteria can build up in the machine’s parts due to lack of cleaning, leading to a sewage-like smell. To prevent this, regularly clean key parts of your machine: the detergent tray, drum, and filter. This keeps both the machine and your laundry smelling fresh.

SEE ALSO: Washing Machine Smells Like Sewage? (here’s why & what to do)

How To Remove Foul Smells From Your Washing Machine Using Natural Ingredients

If your washing machine is causing a bad smell in the kitchen, there are several ways you can get rid of the smell without using chemicals. Read on for natural methods to make your washing machine smell fresh.

Clean The Washing Machine Using White Vinegar

white vinegar in washing machine

Check the filter located in the pump at the bottom front of the machine. If it’s partially blocked, it can cause the washing machine to smell. Remove any blockage and wash the filter in fast running water. 

Inspect the door seal for any mould and gently clean it with a soft, lint-free cloth dampened in white vinegar. Be careful as the rubber seal can easily get damaged. 

Remember to thoroughly rinse the door seal with water after using white vinegar to prevent corrosion of the rubber over time.

Remove the detergent drawer and scrub it clean using a soft brush or toothbrush. If you notice any mould, wipe it away using that soft cloth soaked in white vinegar.

Clean The Washing Machine Using Bicarbonate Of Soda And White Vinegar

Baking Soda

Place ½ cup of bicarbonate of soda in the detergent drawer and run a hot wash. Once the machine has completely finished, run a second wash with ½ cup of white vinegar in the detergent drawer. 

Never allow the bicarbonate of soda and white vinegar to mix as they will produce a frothy substance which will be difficult to remove from your machine.

If after these two wash programs have finished the machine still smells bad, run another wash with a cup of bleach.

Using Soda Crystals To Clean The Washing Machine

To give the washing machine a good clean, pour 500g of soda crystals into the drum and run a hot (service) wash. This is a great way to keep on top of the bacteria and mould that can form in a washing machine which is always used on a cool wash program.

You should run this hot (service) wash at least once a month to ensure the working parts of your machine are free from bacteria, mould, limescale and soap scum.

Change Your Detergent

A person putting laundry detergent into a washing machine

Sometimes it can be the detergent you use which is causing the problem. If you use more detergent than is needed, it can get stuck in patches inside the machine. This then creates the perfect place for germs to breed.

Always use the exact amount of detergent recommended for your area, and always follow the instructions on the packaging.

SEE ALSO: How Often Should You Clean Your Washing Machine?

What To Do Next

If, after doing all of the above, your washing machine still stinks out your kitchen, it’s time to call a plumber. A reputable plumbing company will have the tools and knowhow to advise you on how to solve this annoying problem.

Frequently Asked Questions

Why does my house smell like a sewer when I run my washer?

If your house smells like a sewer when you run your washer, it’s usually because the waste pipe has been fitted wrongly. Check where the washing machine waste pipe runs to and check the U-bend if fitted or that the waste pipe isn’t pushed too far into the sink’s waste pipe.

Why is there a smell coming from my kitchen sink?

If there is a smell coming from your kitchen sink it is usually because there is rotting food stuck in the drainage pipe or waste disposal unit or the U-bend needs cleaning.

How do you clean washing machine pipes?

To clean washing machine waste pipes, you will need to unhook the waste pipe from the stand pipe and remove the other end from the machine. Then try pouring hot water through the pipe to remove any detergent or soap scum. If this doesn’t work, try using a plumber’s snake to remove stubborn clogs. Turn the handle in a clockwise direction to collect the blockage and allow you to remove it.

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