How to unblock a sink
Quick answer: Remove anything you can see in the plughole, then plunge with a sink plunger while blocking the overflow with a damp cloth. If that fails, put a bucket under the trap, unscrew it by hand, empty and clean it, and put it back.
A slow or blocked sink is usually hair, soap and toothpaste in the bathroom, or fat and food scraps in the kitchen. The blockage sits in the plughole or the U-shaped trap just below, which is easy to reach.
Skip the aggressive chemical drain cleaners. They rarely cure a proper blockage and they are hard on your skin, your pipes and the environment.
What you will need
- A sink plunger (flat bottom, small cup)
- Rubber gloves
- A bucket
- An old towel and a damp cloth
- A bent wire coat hanger or a plastic drain-clearing strip
- A bottle brush or old toothbrush
- Washing-up liquid and hot water
Step by step
Clear the plughole
Take out the plug or strainer and pull out any hair, soap and gunk you can see. In the bathroom, a plastic drain strip with barbs is brilliant at lifting hair out.
Run hot water
Pour a kettle of hot (not boiling) water down the drain with a squirt of washing-up liquid. This helps shift fat and soap. In a kitchen, wait a few minutes before trying anything else.
Plunge it
Block the overflow hole with a damp cloth. Put the plunger over the plughole with a couple of centimetres of water in the sink. Push and pull firmly 10 to 15 times, keeping the seal.
Put a bucket under the trap
If it is still slow, put a bucket and towel under the U-bend. Check whether the trap is plastic or metal.
Unscrew the trap
Most plastic traps unscrew by hand: turn the two big nuts anticlockwise. Catch the water. Take care with old metal traps, which can be stiff or corroded.
Clean everything out
Tip the contents into the bucket, wipe the trap clean with your gloved hand and rinse it. Use the brush to clear the pipe either side you can reach.
Refit and test
Fit the trap back with the washers in place and tighten the nuts firmly by hand. Run the hot tap and check for drips at the joints. If it drips, tighten a little more.
Tips
- Put a plughole strainer on the bathroom and kitchen sinks. It catches hair and food before it goes down.
- Pour fat into an old tin or jar when it cools, and bin it. Do not pour it down the sink.
- Hot water and washing-up liquid once a month keeps a kitchen waste pipe moving.
Stop and get help if
- Water backs up in other sinks, the bath, or a toilet. The problem is further down the drain.
- The trap is clean, the pipe is clear and it is still slow. There may be a blockage in the wall pipe or a poor fall on the pipe.
- A metal trap is seized or leaking from corrosion, or you spot damp under the sink that has been there a while.
- You are in rented accommodation: report it to your landlord.
Would you rather we did it?
We cover Sandwich and East Kent. Send us a quick message on WhatsApp, ideally with a photo, and we will come back with a price and a day.
Common questions
Does baking soda and vinegar unblock a sink?
It will freshen a slow drain and loosen a little soap, but it will not clear a proper blockage of hair or fat. Use a plunger or clean the trap.
Can I use drain cleaner?
It is best avoided. Caustic drain cleaners can damage pipes, hurt your skin and eyes and make plumbing work dangerous for whoever deals with it next.
Why does my kitchen sink smell?
Food and fat build up in the trap and pipe. Cleaning the trap and running hot water with washing-up liquid usually fixes it.
More guides
Last reviewed 17 October 2026. This guide is general information for UK homes and is not a substitute for the manufacturer's instructions. If the job involves gas, mains wiring, asbestos, structural work or working at height, or you are unsure, ask a suitably qualified person.