Save up to €250 on selected garden furniture, BBQs & spas > Shop now

How to unblock a sink

Learn how you can shift blockages in your kitchen sink

Having a sink that’s blocked isn’t just an inconvenience, it can release some nasty smells into your kitchen and stop you doing everyday tasks like cooking and washing up. For these reasons, you’ll want to unblock your sink as quickly as possible.

In this guide, we outline how you can unblock your kitchen sink and give you some tips for keeping it clear in the future.

how to unblock a kitchen sinkhow to unblock a kitchen sinkhow to unblock a kitchen sinkhow to unblock a kitchen sink

Unblock a sink with boiling water

Before you try anything more complex, we recommend pouring some boiling water down your plughole. If your blockage has been caused by a grease build-up, the boiling water may be able to melt this grease away, helping to clear your pipes.

Before you pour the boiling water, try and clear as much of the water inside your sink as you can. This will prevent the boiling water being diluted and will make it easier to pour the water directly down the plughole.

pouring boiling water down a plug hole with a kettlepouring boiling water down a plug hole with a kettlepouring boiling water down a plug hole with a kettlepouring boiling water down a plug hole with a kettle

Unblocking a sink with baking soda and vinegar

Baking soda and vinegar are two natural ingredients that when combined, can shift a tough blockage.

1. Clear water from the sink

Before you can start unblocking your sink, you’ll need to remove as much of the water and debris as you can.

2. Pour boiling water down the plughole

Next up, pour some boiling water down the plughole. As with our previous point, this will help shift some of the blockage before you use the baking soda.

3. Pour baking soda and vinegar into the plughole

Next you can pour two teaspoons of baking soda into the plughole. Leave this to sit for a few minutes, then follow with 240ml of white vinegar.

4. Leave the mixture to work

Once you’ve poured these down the drain, you can put your plug in the plughole. You should hear a chemical reaction taking place which will hopefully start to clear the blockage. You can now leave the mixture to work for five to ten minutes.

5. Clear remaining residues with water

Once the mixture has had time to work, pour some more boiling water down the drain to clear any remaining residues. If this hasn't cleared your drain, you can try some of the methods outlined below.

Glass jar filled with baking sodaGlass jar filled with baking sodaGlass jar filled with baking sodaGlass jar filled with baking soda

Unblock a sink with a plunger

The trusty sink plunger is often a go-to for shifting tough blockages. Plungers work by increasing the pressure inside your pipes to push and clear any blockages.

1. Clear water from the sink

To unblock your sink with a plunger, you’ll first need to clear any standing water or debris from the sink. You should also clear as much of the debris from the plughole as you can.

2. Seal the overflow

Next up, you'll need to cover your overflow to create an airtight seal. You can do this with tape or stuff it with a cloth.

3. Add water to cover the plunger

Now you've blocked your overflow and removed as much of the debris as possible, you can add around 5cm of water to the sink to help create a tighter seal as you plunge.

4. Plunge the sink

Position your plunger over the plughole and pump it up and down vigorously, making sure you pump evenly in both directions. Always keep the plunger completely sealed over the plughole.

This motion should help to dislodge the blockage and clear your sink. If the water hasn’t drained, it’s likely the blockage hasn’t moved so check you sealed the overflow correctly then try again.

using a plunger to clear a kitchen sinkusing a plunger to clear a kitchen sinkusing a plunger to clear a kitchen sinkusing a plunger to clear a kitchen sink

Drain unblocker

Specially formulated drain unblockers are another option that can help clear stubborn blockages. These will have their own instructions that you should follow and remember to always wear the right protective equipment.

Check the sink trap

If you’ve tried the methods above and you’ve not been able to remove the blockage, you can try checking the kitchen sink trap itself. This is a relatively easy part of your pipework to inspect.

Although disconnecting the pipework under your sink can feel daunting, with a few simple precautions it can be a pain free process. If you’ve already used boiling water or any chemical drain unblockers, take extra precautions when disconnecting your sink trap as they may still be in the pipework. Before you disconnect the trap, you may want to turn off your water supply at the stopcock. Although this isn’t completely necessary, it could prevent any issues if the tap is accidentally switched on while you’re working.

Before you start unscrewing your trap, have a bucket ready underneath it to catch any water that’s still in the pipes. Working with your kitchen trap is relatively easy as it features connections that can be un-done by hand. Slowly unscrew the plastic pipe connectors on your trap until you’re able to remove it. Don't unscrew the connectors fully until all the water has drained into your bucket.

Once you’ve removed the trap, you can check inside for any blockages and remove what you find. You can also check the pipework surrounding the trap that you can now access. Once you’ve finished, re-attach the trap but leave your bucket underneath until after you've checked for leaks.

Unscrewing a kitchen wasteUnscrewing a kitchen wasteUnscrewing a kitchen wasteUnscrewing a kitchen waste

How to prevent sink blockages

As with many issues around the home, one of the best ways to stop issues occurring is prevention. Here, we outline a few tips that can help prevent sink blockages.

Use a strainer

A simple and relatively low cost addition to your kitchen, a strainer will help stop food scraps and other debris reaching your drain and causing a blockage.

Avoid pouring grease or fat into your sink

Grease and fat are one of the most common causes of sink blockages. When they cool down inside your pipes they will congeal and harden, causing a blockage. Always pour grease or fat into a container and place it in your waste bin.

Pour boiling water once a week

Even with the best care in the world, there’s still a chance fat and grease will make their way into your drain. We recommend pouring some boiling water down your drain once a week to help clear any small build-ups before they can accumulate into a larger blockage.

That concludes our guide to unblocking kitchen sinks. If you've tried the methods above and your sink is still blocked, the blockage may be further down your pipework, or it might just be so stubborn that it's time to call in a professional.