The water in the sink isn't going anywhere, or it drains so slowly you're stood in it in the shower. Most sink and shower blockages are close to the plughole, and you can usually clear them without any special tools.
Kitchen sink blocked
Kitchen sinks usually block with grease, food and soap that build up in the trap and the pipe behind it.
- Hot water and washing-up liquid. Squeeze a good amount of washing-up liquid into the plughole, then pour in a kettle of hot (not boiling) water. Wait a few minutes. This often shifts grease.
- Plunge it. Use a sink plunger. Block the overflow hole with a wet cloth, cover the plughole with the plunger, and pump firmly ten or so times. If you have a double sink, block the other plughole too.
- Clean the trap. Put a bowl under the U-bend, unscrew it by hand, empty it and rinse it out, then screw it back on firmly. Run the tap and check for drips.
- Bicarbonate and vinegar. For a slow drain: half a cup of bicarbonate of soda, then a cup of white vinegar. Leave for 30 minutes, then rinse with hot water.
Shower drain blocked
Shower drains almost always block with hair and soap.
- Lift off the drain cover. Some unscrew, some pull up.
- Pull out the hair. A cheap plastic drain snake (a barbed strip) works brilliantly. Wear gloves.
- Rinse with hot water. If it's still slow, plunge it, or use bicarbonate and vinegar as above.
- Fit a hair catcher over the drain so it doesn't happen again.
What not to do
- Don't pour lots of chemical drain unblocker in one go. It can damage seals and older pipes, and it's dangerous if you then plunge it.
- Don't pour boiling water into a plastic trap or onto a ceramic sink that's full of cold water.
- Don't pour cooking fat down the sink. Let it set and put it in the bin.
When to call a plumber
Call us if more than one sink or drain is slow, water comes back up in a different place (like the shower when you run the kitchen tap), there's a bad smell outside, or the trap is clear and it's still blocked. That usually means a blockage further down the pipe or in the drain. See blocked drains and toilets.
Common questions
How do I unblock a kitchen sink fast?
Try washing-up liquid and hot water, then plunge with the overflow covered. If that fails, unscrew and clean the U-bend trap.
How do I unblock a shower drain full of hair?
Lift the drain cover and pull the hair out with a plastic drain snake, then rinse with hot water. A hair catcher stops it coming back.
When is a blocked sink a plumber's job?
When several drains are slow, water comes up somewhere else, or it's still blocked after you've cleared the trap.