How to Unblock a Sink| Unblocking a Sink

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TOOLS

MATERIALS

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A blocked sink is a common problem in busy households. It’s usually caused by a build-up of everyday debris and food getting caught in the U-bend pipe below the sink.

Unblocking a sink is a straightforward task you can easily tackle yourself. Consider watching our handy how-to video before you begin so you can see the methods in action.

Place a blaster cup or plunger over the plug hole and block the overflow with a wet cloth to pump out small blockages.
Pour a liquid drain unblocker down the plughole to dissolve stubborn food and grease build-ups.
Push a flexible plumber's snake down the pipe to catch obstructions, or unscrew the trap directly to manually clear debris.

Tools and Materials

Using a plunger

Block the overflow hole with a wet cloth to create an airtight seal and place your blaster cup or plunger directly over the plug hole.

Gently pump the plunger or blaster cup up and down whilst keeping the overflow firmly covered. This should be enough to dislodge most small blockages.

Chemical and natural cleaners

If this fails to clear the blockage then try using a liquid drain unblocker. Open a window to ventilate the kitchen first. Then, following the manufacturer's instructions, pour the liquid drain unblocker down the plughole. Alternatively, you can use baking soda and a cup of white vinegar to break down debris naturally.

Wait for the fizzing reaction to break down the debris, then thoroughly rinse the pipe with hot water.

Using a plumber’s snake

Carefully push your coil cleaner down the plughole, twisting as you do so.

Once you reach the obstruction, twist and pull the coil cleaner until the blockage is broken up. Retract the tool and rinse the sink with cold water.

Clearing the waste pipe

For more stubborn blockages, you may need to access the trap directly. Most debris collects in the U-bend underneath the sink - this is ‘the trap’.

Turn the water supply off at the mains stopcock and place a bucket directly underneath the U-bend trap.

Carefully unscrew the trap from both ends. You’ll need to use a wrench if the fittings are especially tight.

Empty the trapped water into your bucket and throw any solid waste directly into the bin.

Replace the trap using some PTFE tape on the threads to prevent leakages. Make sure you don't overtighten the threads when replacing the trap, then turn the water back on at the mains stopcock.

Hopefully we were able to help you find the right method for unblocking your sink. If you’re having further problems with your sink such as leakages, read our guide on how to fix a leaking kitchen sink.

FAQs

Sinks usually clog because everyday debris, cooking oils, and coffee grounds build up and get stuck in the U-bend trap below the sink. To prevent future blockages, always throw food waste in the bin rather than washing it down the plughole. And regularly rinse your pipes with hot water and soda crystals, or a cup of white vinegar, to keep them clear.

Bathroom sinks frequently get blocked by hair and soap scum rather than food waste. A flexible plumber's snake is best suited for this. Carefully push it down the plughole and twist it around the U-bend to hook and pull out the trapped debris safely.

Once your blockage is cleared and the water is draining freely again, it is a good idea to thoroughly flush the system. Rinse the pipes through with plenty of hot water to wash away any remaining residue. Pouring a cup of white vinegar down the plughole afterwards also helps to break down lingering grime naturally.

The most common signs include water draining very slowly, completely stopped-up sinks, gurgling noises coming from your plughole, and unpleasant odours rising from the pipes. If water starts backing up into other sinks or appliances, the blockage is likely severe and located further down your main waste pipe.