If you are not an experienced plumber, you could be forgiven for asking why the pipe work found below sinks typically features a U-bend fixture.
The U-bend, sometimes referred to as a P-bend or J-bend, is known as a trap and is there to stop bad smells from drains coming back up the pipe and creating unpleasant odours in your home.
How they work
The trap works by keeping a small amount of water in the U-bend that stops smells from getting through. If there is a bad smell of drains in a home, the first port of call for most plumbers is to check whether the U-bend is dry.
Virtually all plumbed fixtures in a home will have a drain trap of some kind. U-bends in toilets are easy to spot as they are visible while larger plumbing fixtures, such as showers, baths and washing machine drains, will also have drain traps but they tend to be hidden behind walls, under the floor or behind shower trays etc.
Slow draining plughole?
If there is a blockage that is slowing down the drainage of a sink or a bathtub, many times the problem will be located in the curve of the trap where items can build up. Blockages of this kind can be unclogged with a tool called a plumber’s snake. Other remedies include using a plunger or a chemical drain opener.
Many modern plumbing traps are now manufactured with a clean-out valve at the bottom of the curve in the pipe, which makes it easier to access the plumbing trap for cleaning and draining.
The little helper for butterfingers
But while a trap may cause a blockage from time to time, it can also offer a benefit to people who accidentally lose a valuable item down the sink. U-bends tend to capture items like rings and earrings that sink in water.