How to Unblock Kitchen Sink

TL;DR: To quickly unblock a kitchen sink, start by flushing with boiling water (with cold water running if you have a composite sink), then use bicarbonate of soda and vinegar, followed by a plunger if needed. For stubborn clogs, clean the U-bend. Prevent future blockages by avoiding grease and food waste in the drain.

If you want to know how to unblock kitchen sink drains quickly and safely, we can help. With over 20 years of experience in the kitchen industry, we have seen every kind of blockage and know the most effective ways to deal with them. Whether it is caused by food debris, grease build-up, or something more stubborn, there are proven methods you can try before calling a professional.

How to Unblock Kitchen Sink Without Causing Damage

Blocked sinks are one of the most common household issues, but they do not have to be stressful. By understanding the cause and using the right tools, you can clear most blockages in a matter of minutes.

Identify the Cause of the Blockage

Before starting, check whether the water is draining slowly or not at all. Slow drainage often means a partial blockage, while standing water usually indicates a complete blockage. Common causes include food particles, grease build-up, coffee grounds, or small objects that have fallen into the drain.

Boiling Water Flush

If the blockage is caused by grease or soap build-up, boiling water can help break it down. Carefully pour a kettle of boiling water into the sink in stages, allowing it to work through the pipes between each pour. For composite sinks, always run the cold tap at the same time to avoid thermal shock.

Bicarbonate of Soda and Vinegar

A natural and effective method involves pouring half a cup of bicarbonate of soda into the drain, followed by half a cup of white vinegar. Cover the plughole and leave for 10–15 minutes, then flush through with hot water. This helps break down organic material and odours.

Use a Plunger

If water is still not draining, a plunger can help dislodge the blockage. Make sure the plunger cup covers the drain completely, then push and pull in short, sharp motions. Repeat several times and then test the water flow.

Check the U-Bend

For persistent blockages, you may need to remove and clean the U-bend under the sink. Place a bucket underneath to catch any water, unscrew the fittings by hand, and clear any debris before reattaching.

Preventing Future Blockages and How to Unblock Kitchen Sink

Avoid pouring fats, oils, and grease down the sink, and use a sink strainer to catch food particles. Regular cleaning helps prevent build-up. Our guides on how to clean a composite sink and how to remove tea stains from composite sink include practical tips for keeping your sink in top condition.

Now you know how to unblock kitchen sink drains effectively, you can save time and avoid costly call-outs. If you are upgrading your kitchen, take a look at our kitchen sinks collection for high-quality and long-lasting designs.

For more advice on unblocking drains, see the Which? guide to clearing a blocked sink.