Clear a blocked bathroom basin by plunging first, then removing and cleaning the trap underneath.
UB-01Get set upClear out the cupboard under the basin and lay old towels on the floor to catch drips. Put a bucket under the trap (the U-shaped or P-shaped pipe under the basin) ready to catch water. Put on rubber gloves before you start.
UB-02Try a plunger firstPush a wet cloth firmly into the overflow hole (the small slot near the top of the basin) so the plunger can build suction properly. Fill the basin with a few centimetres of water so the plunger head is covered, then push down and pull up sharply 10 to 15 times without breaking the seal. Run the tap to see if the water now drains away.
UB-03Check if it's clearedRun the tap for a minute and watch how fast the water drains. If it drains normally, skip to the tidy-up step. If it's still slow or blocked, move on to the trap.
UB-04Remove and empty the trapMake sure the bucket is directly under the trap, then loosen the two slip nuts by hand or with pliers if they're stiff. Slide the trap down and off, letting the water and debris fall into the bucket. Most bathroom traps hold hair, soap scum and limescale — this is usually where the blockage is.
UB-05Clear the trap and the pipe beyond itRinse the trap out under another tap or outside until it's completely clear. Push a hand-crank drain snake (or a straightened wire coat hanger) a short way into the pipes on both sides of the trap to pull out any remaining hair or debris. Don't force it hard — a gentle twist and pull is enough.
UB-06Refit the trapCheck the rubber washers inside the trap are still soft and sitting flat, and swap them if they look worn. Slide the trap back into place and tighten the slip nuts by hand — snug is enough, overtightening can crack plastic fittings.
UB-07Test for leaks and flowRun the tap for two to three minutes and watch the joints under the basin for drips. Check the water drains away quickly and normally. If a joint drips, tighten the nut slightly further rather than forcing it hard.
UB-08Tidy upBin the debris from the bucket — never tip it back down the drain. Wipe up any spills, put the towels in the wash, and give the pliers and plunger a rinse before putting them away.