Direct Line magazine

How to unblock a sink

Updated on: 10 December 2020

Unblocking a sink with a plunger.

Most of us have encountered a blocked sink. That weird smell in the kitchen when you first walk in, the way the water slowly drains out over the course of minutes, or odd gurgling noises as it drains… they’re all tell-tale signs of a blockage.

Fortunately tackling a blocked sink is something well within the reach of most people. There’s no magic to unblocking a sink, just follow the tips in this article and get ready to let it flow.

There's nothing worse than a blocked sink

Well that’s exaggerating things a tad, but a blocked sink can be inconvenient, smell awful and become an incubating ground for bacteria. So knowing how to unblock a sink is something that everyone should know how to do.

You don’t need fancy tools to unblock a sink, or any special skills at DIY or plumbing. But it helps to not be squeamish, as you’ll be encountering all kinds of slime and food remnants.

woman unblocking a sink

Best ways to unblock a sink

Here’s how to unblock a sink, in three easy stages. Try them each in turn, and hopefully at least one of them will get your sink unclogged and functioning properly again.

Take the plunge

The first step is to grab a plunger and get to work on it. Plunging sucks air out of the pipe and then forces it back in, which helps to dislodge the blockage. There’s no special trick to unblocking a sink with a plunger. Place the cup over the plughole, and ensure a seal is formed, then drive the handle down and up in a pumping action. You’ll know the blockage is clear when you fill the sink up and it drains quickly.

Blast it out

Sometimes a hard burst of water can push out whatever is blocking your sink. Take a plastic milk bottle or 2-litre drink bottle, fill it with hot water, tip it upside down with the bottle hole against the plughole, and squeeze as hard as you can. The fast, directed flow of water may well fix the problem.

Down the drain

Sometimes a plunger can’t unblock the sink because the blockage is dense and greasy and the suction of the plunger just can’t dislodge it. So you need to do something to break down the blockage. There are a lot of hardcore drain unblocking solutions on the market, and though they will often get the job done they’re pretty harsh, and can linger in the drain and around your sink too.

A more friendly solution to unblocking a sink uses a simple mix of baking soda and vinegar. First, pour a load of baking powder down your plughole. Then tip in the vinegar. You’ll hear a lot of fizzing, and may even get some froth coming back up the plughole. Once the chemical reaction subsides tip some hot water down to flush the pipe through.

If that doesn’t work you can also use bleach to dissolve blockages. The best approach with bleach is to pour some through the plughole last thing at night and then flush with hot water in the morning.

You may want to give the sink a quick plunge afterwards as an extra measure to dislodge any clumps of gunge.

Round the bend

If none of the above work, then it’s time to roll up your sleeves and get your hands dirty. Most blocked sinks happen because the U-bend gets clogged up, and sometimes the only solution is to remove the U-bend and clear it out by hand. To do this you’ll need:

  • Small bucket or dish

  • Plumber’s tape

  • Wire coat hanger

Look under your sink and find the U-bend, it’s the first bend in the pipe immediately below the plughole. Put your bucket/dish under the U-bend and carefully unscrew the section of pipe. The U-bend has two sets of threads, one at either end. As you loosen them any backed up water will drain out, so take your time. Once the flow of water has stopped remove the U-bend and use the wire coat hanger to clean out the inside of the pipe, you can also use a dishcloth and warm water to help clean everything out.

Once it’s all clean, fix the U-bend back into place, using plumber’s tape to make it watertight if needed. Run the tap to make sure the U-bend is watertight.

If none of the above work then the blockage could be situated elsewhere and it’s probably time to consider calling out a plumber to get to the bottom of the issue.

Avoiding a blocked sink

The very best way to avoid a blocked sink is to stop certain things going down the drain. Keep an eye out for:

  • Food

  • Tissues

  • Drinking straws

  • Cotton wool buds

  • Bits of plastic

  • Paper

  • Basically anything that isn’t water or another liquid

Prevention is always better than cure, and a fair bit cleaner and less smelly too. But if your sink does get blocked, don’t let it get you down. Grab a plunger and show that blockage who’s boss.

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