Why Does My Sink Gurgle When the Washing Machine Drains?

No, a properly functioning drainage system should operate quietly. A gurgling sink is often a sign that air cannot move freely through the drainage system, so if you notice this then you probably have a blockage somewhere in your drainage system. . The blockage could either be in the main drain pipe, the air vent, or both.

Can a blocked vent pipe cause sink gurgling?

Yes. This is often one of the most common causes.

Every drainage system has an air vent, which enables water to flow through unimpeded and prevents pipes from becoming vacuum-sealed due to a lack of air. Often, utilities like a washing machine or dishwasher will have their own vents which connect to the main air vent in your house. One of the most common causes of a gurgling sink is a blockage in this main air vent. When there is a blockage, air can get trapped in the pipes. As the air tries to escape through the water in the pipes, it creates gas bubbles, and this is most often the source of the gurgling sound in your sink.

What else causes a sink to gurgle when the washing machine empties?

The most common causes are:

• A blocked or partially blocked vent pipe


• Build-up of fat, oil and grease in the drain


• A partial blockage in the main drain


• Older plumbing systems or a poor pipe layout

Appliances such as washing machines and dishwashers are usually connected to the same drainage and ventilation system as sinks, which is why you can hear noises coming from the sink if any part of the system is restricted.

Is it safe to clear a blocked vent pipe yourself?

If the vent outlet is safely accessible, a visible obstruction may sometimes be removed by diy methods. Find out how to unblock a sink by yourself in our article ‘What should I do if my sink is clogged?’.

Many homeowners attempt to fix blockages using chemical drain cleaners. While these products may temporarily break down some waste, they often do not fully clear blockages, and over time, residue can build up elsewhere in the system, causing recurring problems.

Chemical cleaners can also:

• Damage pipework due to their corrosive nature


• Shorten the lifespan of drainage systems


• Harm the environment

Find out more reasons why you shouldn’t use harsh chemicals as a drain unblocker in our article ‘Should you use caustic soda to unblock drains?’.

Deeper or internal blockages will require professional equipment and skilled engineers, such as the team at Lanes, who can carry out CCTV drain surveys and clear any stubborn drain blockages.

The most effective solution to solving this problem is to diagnose it properly.

A professional can identify the cause by:

• Listening to where and when the gurgling occurs


• Checking airflow and drainage performance


• Carrying out a full diagnostic inspection

When you have a drainage expert clear the blockage, they will remove the waste material and dispose of it properly, preventing further problems from emerging and ensuring that the gurgling sound is gone. Provided you take good care of your drainage system, by disposing of food and other waste in the bin rather than down the drain, you can prevent further blockages from arising and keep your pipes in good working condition..

Domestic Drain Unblocking Services from Lanes Drainage Services

With decades of experience resolving domestic drainage issues, Lanes Drainage Services provides fast and professional solutions for drainage problems across the UK

If you need domestic drain unblocking services, contact the experts at Lanes Drainage Services today. Call us day or night on 0800 526 488 for a free quotation, or fill out our online enquiry form to arrange a call back at your convenience.