Clear a blocked kitchen sink safely, from plunging to dismantling the trap and testing the flow again.
KS-01Clear the space and get set upEmpty the cupboard under the sink and lay down old towels to catch drips. Get a bucket ready to catch water from the pipework. Put on rubber gloves before you touch anything from the drain.
KS-02Try a plunger firstPart-fill the sink with a little water so the plunger has something to push against. If you have a second bowl or an overflow hole, block it with a wet cloth so the pressure goes down the blocked pipe, not sideways. Push down and pull up firmly several times, then check if the water drains.
KS-03Remove and empty the trapIf plunging doesn't work, the blockage is usually in the U-bend trap under the sink. Put the bucket directly underneath it, then unscrew the two slip nuts by hand or with pliers if they're stiff. Let the trap drop and empty the water and debris into the bucket.
KS-04Clean out the trapClear any gunk, food or grease out of the trap with an old brush or your gloved fingers. Rinse it under a tap or with water from a jug so you're not relying on the blocked sink. Check the two open pipe ends with a torch for any visible blockage.
KS-05Clear a deeper blockage with a drain snakeIf the trap was clear, the blockage is further down the waste pipe. Feed a sink auger or drain snake into the pipe from the trap opening, turning the handle as you push. Wind it in until you feel it stop, then work it back and forth to break up the blockage before pulling it out.
KS-06Refit the trapPush the trap back together and hand-tighten the slip nuts, checking the rubber washers are seated properly inside. Don't overtighten plastic fittings — snug is enough, and you can nip them slightly further with pliers if they still weep water later.
KS-07Test the flow and check for leaksRun the tap for a minute and watch how fast the sink drains. While it's running, check under the sink for any drips around the trap joints. If it drips, tighten the nut slightly more and check again.
KS-08Tidy upBag up the debris from the bucket and bin it — don't pour grease or food waste back down the sink. Wipe down the cupboard, dry the pipework, and put your tools away.