Let’s look at problems that happen underneath sinks. Under every sink, whether kitchen or bathroom is a drainage system. However the waste water does not just go down directly into the drain through a straight pipe, as an open pipe connected to the sewer would be both very smelly and possible dangerous to the health of the family that lived in the home. So between the sink and the drainage pipe is a curved section of pipe, sometimes called a U-bend or P-trap. The trap keeps a permanent layer of water init which does not drain out, and this water prevents the obnoxious sewer gases from entering the sink. It is important to the plumbing system in your home that drain traps are kept in good working order, and your local plumber can check these for you. If there is a problem with the sink drain pipe, or more usually with the seal on the drain pipe, then the water in the trap may leak out, causing a potential health hazard, not to mention the smell. This leakage or water seepage may happen gradually and is not always easy to spot. In contrast if there is a blockage or clog inside the trap, you will find out immediately, as the water won’t drain out of the sink, or it may drain out very slowly. Clearing the blockage is a job that you may wish a plumber to tackle, as sometimes it can be difficult.
The drain trap has a number of components. The first part is where the pipe from the sink comes down underneath the sink and enters the trap joint. This pipe which joins the sink outlet flange to the trap is sometimes called the tailpiece. This enters a curved section of pipe, which is the trap, and then on the other side is a drain pipe which takes the waste water away to the sewer drain. The trap has two seals and connections, one at each end to the tailpiece and drainpipe. The trap and pipes may be made of metal or more commonly PVC plastic. Metal is more likely to suffer rust or corrosion and most homes these days use the PVC version. However these can also be damaged, especially by an untrained plumber using a plumber’s auger to clean out a blockage, as the auger spring tip can damage the water seal.
Usually the trap is connected to the pipes using a compression fitting where a nylon ring acts as the seal and a plastic slip nut is tightened from the trap, compressing the nylon seal against the pipe. It is possible that the compression slip nuts may have worked loose (especially on a sink with a cupboard underneath where family members may be storing items in and may have brushed past the nut), and the leaking trap can be repaired by tightening the nut. That is an easy repair.
However the re may be a different plumbing problem if a metal trap is corroded, if the compression nuts have been cross-threaded (damaging the threads) or if the trap is damaged in another way. In these cases, it will be necessary to replace the trap with a new one from a plumbing supply store. It is also possible to replace the nylon sealing washers, but it still requires the removal of the trap to be able to switch over the washers. Most traps are of a standard size, with two inch for sinks or four inches for toilets, however it is a good idea to take the tailpipe to the store just to have the technician double check the pipe size. Make sure there is a bucket to catch the waste water when the trap is undone, as this can be a very messy business unless done by a professional plumber.
Usually the trap is connected to the pipes using a compression fitting where a nylon ring acts as the seal and a plastic slip nut is tightened from the trap, compressing the nylon seal against the pipe. It is possible that the compression slip nuts may have worked loose (especially on a sink with a cupboard underneath where family members may be storing items in and may have brushed past the nut), and the leaking trap can be repaired by tightening the nut. That is an easy repair.
However the re may be a different plumbing problem if a metal trap is corroded, if the compression nuts have been cross-threaded (damaging the threads) or if the trap is damaged in another way. In these cases, it will be necessary to replace the trap with a new one from a plumbing supply store. It is also possible to replace the nylon sealing washers, but it still requires the removal of the trap to be able to switch over the washers. Most traps are of a standard size, with two inch for sinks or four inches for toilets, however it is a good idea to take the tailpipe to the store just to have the technician double check the pipe size. Make sure there is a bucket to catch the waste water when the trap is undone, as this can be a very messy business unless done by a professional plumber.