How to Attach P-Trap to Drain Pipe

A p-trap is one of the most important things when it comes to plumbing. It is needed as it helps retain water and stops sewer gases from getting into your kitchen.

If you fail to do the PVC trap installation properly or fail to maintain it, it will create issues for the particular sink it serves. It could also lead to more universal issues.

For your p-trap to work properly it has to be installed according to the right procedure which you can find online or from the manufacturer. That said, if you’re not confident enough it’s worth getting a plumber to do the job for you.

Ensure you get a certified one to install or just replace your existing p-trap.

However, if you often handle plumbing tasks by yourself, below are the straightforward procedures on how to attach p-trap to drain pipe. These show both how to do a p-trap connection to wall or to the floor.

How to Install a P-Trap into a Floor Drain

A floor drain refers to a plumbing feature usually installed in floors to help eliminate any standing water from your floor.

These come in different shapes, all of which should have a strainer. The strainer helps to prevent injuries or any foreign objects from entering the drain.

To install a p-trap to a floor drain, you need the following tools:

  • A floor drain
  • A p-trap
  • Glue for pipes
  • Pipes
  • Coupling

 Step 1: Install the Drain on the Floor

Start by finding a hole on the floor then cut it so that you can install the drain accordingly. While installing it on the floor, ensure you screw the drain properly in place.

Ensure the extension is well fitted through the hole and that it also extends to that floor underneath.

Step 2: Install the Extender Pipe to the Drain’s Assembly

Right after you have confirmed that the drain is properly installed on the floor, proceed to the extender pipe.

Install it to the drain assembly. For you to do this accordingly, start by cutting a section of the pipe. Ensure that you make a square shape cut on it.

Step 3: Smear Glue on the Pipe

Get the glue and smear it on the inside part of the coupling. Use more of it on the pipe that’s extending below the floor. Combine the two pipes and firmly hold them attached to each other. Do this until the glue is set.

Step 4: Install the P-trap

When the glue is properly set, proceed to install the p-trap. Begin by identifying the straight line extending from the set drainpipe and your house’s drainage system as well. These two will eventually have to be connected.

Step 5: Connect the P-trap to the House Drainage System

Pair your p-trap to the house drainage system as well as the already set drain pipe. This p-trap should follow a straight line.

You can then glue together both sections of the p-trap. Do this ensuring it’s pointing in a straight line from the eventual line of the drain.

Step 6: Install the Pipe

To complete this installation process, cut the drainage pipe’s end point then install the pipe to the tee.

It is important to ensure that your floor’s drains have been piped with p-traps as this creates a water seal.

The water seal facilitates easy drainage while preventing odors that could come from the drain. P-traps ensure dirt from the floor accumulates faster and the drain clogs easily.

When you are purchasing a floor drain, make sure you get one that allows both sand and dirt to settle properly without getting carried into the drain pipe.

How to Attach a P-Trap to a Wall Drain

For your p-trap to function accordingly, you need to properly install it on your wall. Here, the p-trap is properly connected to the pipe that exits the sink and the other to the wall drain pipe.

Step 1: Slide the Shorter Side of the P-trap into the Part That Drops to the Sink’s Drain

Once you’ve done this, align it to the opening found on the wall of the trap arm. This can be achieved by moving it up and down until it is in place.

In case you’re unable to move the p-trap higher up the tailpiece, cut the tailpiece using a hacksaw. However, in case the p-trap is above the wall drain, it’s worth buying a tailpiece that is longer.

You should install the trap directly under the drain. This will ensure that you have an easier time confirming whether or not it is holding water as it should be. This also ensures greater water gravity.

Step 2: Separate the Lower Part of the P-Trap

Once you’ve taken it apart, insert the trap arm to the wall drain. Fit it properly until it goes as far as possible.

You can then start pulling the trap arm from the wall up to the point where it will fit properly with the U-shaped part at the top of the trap.

Ensure the trap arm does not completely come out, otherwise, you will be forced to buy another one.

If you notice the trap arm still extending past the U-shaped part when in the wall fitting, cut it. A hacksaw will help you cut it to the required length.

Step 3: Insert the Trap Arm Back into the Wall Drain

Once you have inserted it make sure the trap arm is aligned to the trap. Thread it lightly on the slip nut. It is important to note that you should never tighten it in this step of the process.

Step 4: Tighten the Slip Nuts

Only when all the parts of the trap are properly joined should you tighten the slip nuts found on the wall drain fittings. Also, tighten the ones on the tailpiece.

You can use some water pump pliers to tighten them further. Check one more time if the p-trap aligns with the wall drain. If it does not, you should cut it accordingly.

When properly installed, the p-trap will properly retain water and prevent any sewer gases from going into your kitchen.

What is a P-Trap and How Does it Work?

A p-trap is the U-shaped piping that’s found underneath your sink. It is crucial to the overall plumbing in your home and should therefore be installed wherever there exists an open drain line. This is if the drain line releases water into a drain waste vent system.

Whether you want to install a bathroom p-trap or elsewhere in your home, you need to follow the right steps in doing so. It works by providing an airtight seal that stops sewer gases from being released into your house via the drain line.

The p-trap does this by holding some of the drain water in its lower bend that is J-shaped. It also traps all those solids that could clog your sewer or the drain line.

These p-traps work properly thanks to the water seal found in a curve located on the trap. With it, the solids will remain in the trap until they break down.

Every time you use the trap, more water is introduced into the p-trap. This water clears away all the remaining traces of dirt.

How to Connect Sink Drain to Wall Pipe

The following process should be followed when connecting your sink drain to the wall pipe.

Step 1: Connect Tailpiece to the Strainer

Start by connecting the tailpiece to your kitchen strainer. While doing this, ensure the threads are properly aligned to the kitchen sink strainer’s threads. Tighten it in a clockwise direction.

With a drainpipe, fix the tailpiece. Ensure you insert a rubber gasket to the drainpipe to ensure the seal is watertight and that the tailpipe is well connected.

Step 2: Install the P-trap to Connect the Drain Pipe from the Sink to Wall Pipe

To do this, slide the shorter side of the p-trap you’re using to the tailpiece. After this, rotate this p-trap ensuring you’ve properly aligned the trap arm with the wall drain fitting.

Step 3: Cut the P-Trap

Use a hacksaw to cut the p-trap. This will help you in adjustment if the arm is below the wall fitting and you’re unable to move the drainage pipe higher.

Once the trap is properly aligned, fix it to the wall drain ensuring it’s aligned to the trap’s u-shaped portion.

Step 4: Tighten the Slip Nuts

Tighten the slip nuts found on the wall drain once everything is properly aligned so as to complete the process.

If you notice that the wall drain is too far from the sink, consider getting an extra pipe to help connect the p-trap to the wall drain.


Attaching a p-trap to a drain pipe is highly important. The steps are easy to follow whether you choose to go with a floor drain or a wall drain for the process.

However, if you still feel like you are not confident enough to do it yourself, don’t risk it. Just a single error could ruin your home’s carefully created plumbing system. A plumber may come in handy instead.

However, through this guide, the sink p-trap should be attached to the drain pipe perfectly.

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