If you are looking for information on how to replace your drain trap, you probably have a pretty good idea already of how drain traps work. Keep reading to learn how to replace your drain trap and save money on home repairs.

A drain trap is a pipe that's located under or inside a plumbing fixture. Drain traps are different shapes, but your kitchen and bathroom sinks most likely have what is called a P-trap. It is shaped like a P, because it is basically a U-bend with an additional 90 degree fitting on the outlet side. You might also hear this kind of drain pipe simply called a sink pipe. This is the kind of drain pipe you are probably looking to replace, so this article will focus on this kind of drain trap.

If you drop something into your sink by accident, like a piece of jewelry or a key, the sink trap will capture this and allow you to rescue it by disassembling the trap. They are quite useful in this way.

Another reason you might want to disassemble your sink trap or drain trap is to clean it out, or fix part of it that is not working, or even replace the whole thing.

It is very important that you replace your drain trap if it is leaking, because drain traps always have a plug of water within their curved sections that protect you from harmful sewer gases entering. Say your sink trap is leaking, this water plug might disappear and those gases enter your home, which can be very dangerous. So if your drain trap is leaking, do not think of this as something to worry about later – learn how to replace it right away!

What Tools Do I Need to Replace a Drain Trap

You will need a few special tools to replace a drain trap under your kitchen or bathroom sink. These tools are quite easy to find and you may even have most of them already.

  • Wrench
  • Bucket
  • Screwdriver
  • Plumbers' joint compound or tape

In addition to the tools above, you will of course also need a replacement drain trap or the other parts that you are replacing.

What will you expect to find in your new drain trap assembly?

There will be several different parts. Go look under your sink now. Do you see a short piece of pipe extending down from the drain outlet flange? This short piece of pipe is called a tailpiece.

Now look for a curved section of pipe connected to the tailpiece. This is the drain trap itself. Your trap may be one piece, or it could also be two sections coupled together.

Then, you will notice another piece of pipe that goes from the end of the sink trap to the drainpipe outlet in the wall or floor. This pipe is the drain extension.

Before you jump in to replace your drain trap, do check that the slip nuts holding the drain trap assembly to the drain and drainpipe are still nice and tight. If they have loosened, this could be causing your problem. Just go ahead and tighten them. Hopefully this will solve the problem and save you some time and money.

If the slip nuts are already tight, or if tightening them doesn't help, then look to see if the metal has corroded at all. Also check if the slip-nut threads are damaged. Look for any other damage like cracks or dents. If you see any of these things than you will definitely need to replace your sink trap.

What kind of drain trap assembly or parts do you need?

This totally depends on your existing set-up and what you want. If your sink trap is going to be visible, then a chrome-plated thin-wall brass sink trap is attractive and works quite well.

If all you care about is longevity and you don't want to have to repeat this job too soon, then go for a polypropylene plastic sink trap. These are the best when it comes to performance.

Try and avoid an ABS plastic trap. These traps are not really the best especially if you are running a lot of boiling hot water or strong household chemicals through your pipes. They don't hold up well. Actually, some plumbing codes don't even allow these any more.

So now you've chosen your material, what size of trap do you need? Usually kitchen sinks will have 11/2-inch traps and bathrooms tend to have 11/4-inch traps. Measure your existing set-up or take it with you to the store.

Is trap replacement difficult? No, usually not. Below you will get the instructions to replace your sink trap.

  • Does your trap come with a clean-out plug? Check the bottom of the curved section for this and if you see it, then you will need to remove the plug with a wrench. Allow the water in the trap to drain into a bucket. If you don't have a clean-out plug, then just unscrew the slip nuts. Slide them out of the way for now.
  • Is your trap a swivel type? Then the curved trap section should come free. But just make sure to keep the trap upright when you remove it. Now pour out any water after the part is free.
  • If the trap is not a swivel type then it will be a fixed type. In this case, you will need to take off the tailpiece slip nut at the drain flange.
  • Shove the tailpiece down into the trap itself. Now twist the trap clockwise until you are able to drain the water in the trap. Pull the tailpiece free. Unscrew the trap from the drain extension or drainpipe.
  • Replace the parts in the right order. Be sure you line up the slip nuts and compression seals on the appropriate pipe sections. Once everything is nicely lined up go ahead and tighten the nuts, but be sure not to over-tighten them. They should be snug but not so tight that it's impossible to loosen them again.

Now that everything's back in place, you should run some water right away. There are two reasons for doing this:

  1. First of all, you should check for leaks to make sure that everything has been correctly installed.
  2. Secondly, remember that one function of the trap is to protect you against sewer gases. So you need to fill up the trap with that water plug so it can perform this function.