A blockage starts quietly: the basin or bath drains a little slower and an unpleasant smell appears. Hair, soap, grease and food scraps stick to the pipe walls layer by layer until the drain closes completely.
Do not put it off: the washing machine and dishwasher often drain into the same pipe, and a full blockage while they are running can flood your home and the neighbours below. Here is how to clear it, starting with the simplest method.
What you will need
Important: Switch off any washing machine or dishwasher connected to the drain before you start. Wear gloves and never mix different chemical drain products.
Step 1
Start with a plunger
For a minor blockage of hair or food scraps, a plunger is often enough. Block the overflow, press the rubber cup firmly over the drain and pump the handle sharply several times to build pressure in the pipe.
The plunger never touches the pipe itself, so it cannot damage it. If the water drains after a few attempts, flush with hot water.
Step 2
Break up the blockage with a snake
If the blockage is deeper, use a drain snake. Feed the end into the pipe and push it on, turning the handle clockwise and working the snake back and forth to break up and hook the debris. Pull it out and flush the drain.
This method is reliable but messy, so keep a bucket and rags to hand.
Step 3
Clean the trap
The trap under the sink collects most of the grease and debris. Place a bucket underneath and unscrew it carefully: dirty water will pour out. If a nut is seized, apply WD-40 Specialist Penetrant and wait a few minutes.
The inside of the trap and pipe is coated with a greasy film. Spray it with WD-40 Multi-Use and wipe it out with a rag, wearing gloves: the product softens greasy deposits so they come away easily.
Step 4
Clean the shower and bath drain
A shower or bath drain blocks mainly with hair. Unscrew and lift off the grille, take out the water seal cup and remove the hair and soap scum.
Rinse the parts, treat them the same way as the trap and refit them, checking that the seal sits evenly. Lubricate the grille screws, which rust in the constant damp, before screwing them back in.
Step 5
Treat the pipe and flush
With the trap removed, insert the straw of WD-40 Smart Straw into the waste pipe and spray for a few seconds so the product runs down the pipe walls. Leave it for at least 10 minutes without rushing, to give the deposits time to soften.
Refit the trap and flush the drain with hot water. If it still drains slowly, repeat the treatment or run the snake through again.
Step 6
Tidy up
Wash your tools, check the trap joints for drips and clean the sink. Wipe rust marks on a stainless sink and on chrome fittings with WD-40 Multi-Use: it cleans and leaves a thin protective layer. Afterwards, wash the sink with water and washing-up liquid.
Tip: Fit strainers to every drain, and clear hair from the shower grille once a week. It is the cheapest way to forget about blockages for years.
What next
Clean the traps and shower drain every 2-3 months as routine, and more often in the kitchen. If all your drains block at the same time, the problem is in the main stack and you need a plumber.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
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