HWritten by a qualified plumbing and heating engineer·

Slow draining sink — how to clear it yourself

Free DIY guide — no sign-up required. written by a qualified plumbing and heating engineer.
DIY Friendly💷 £0£1520–30 min

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Most likely cause & what to check

1

First try the simplest fix: put the plug in, fill the sink with hot water, then remove the plug quickly — the weight of water may push the partial blockage through.

2

Use a plunger: cover the overflow hole with a wet cloth (to create proper suction), place the plunger over the drain, and plunge firmly 10–15 times. This works best for sink blockages close to the drain hole.

3

Clear the U-bend (trap) under the sink: place a bucket under the trap, unscrew the trap — it's usually hand-tight. Remove any hair, grease, or debris. Rinse and replace.

4

For a kitchen sink, the blockage is often grease-based. Pour a kettle of boiling water down the drain (safe for metal or ceramic sinks and pipes, but not for plastic pipes or older joints — use hot water, not boiling). Add a good squeeze of washing-up liquid first.

5

Bicarbonate of soda and white vinegar: pour half a cup of bicarb down the drain, followed by half a cup of vinegar. Cover and leave for 30 minutes, then flush with hot water. This works on organic/grease blockages.

6

For bathroom sinks, hair is usually the culprit. A drain snake or zip-it tool (a thin plastic strip with barbs) can pull the hair mass out from just below the drain cover without dismantling anything.

7

Avoid using caustic soda or strong chemical drain openers regularly — they damage seals, cause pipe corrosion over time, and are harmful if they splash back. Use enzyme-based cleaners for regular maintenance instead.

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🛠 Tools & materials you may need

Rubber glovesPlunger BucketPliers or pipe wrench

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