How to Connect P-trap to Wall Drain

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Are you trying to figure out How to Connect the P-trap to Wall Drain? Well, the good news is that you’ve come to the right place.

Getting a P-trap connected securely and properly is key for making sure that your sink or bathtub has proper drainage and it doesn’t just overflow randomly! But don’t worry although it might seem intimidating at first, once you follow our simple instructions below you’ll be able to do this like a pro in no time. 

Let’s get started!

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

Orhemus Brass Round Bottle P Trap, Basin Sink Waste Trap Drain Tube Kit Adjustable Height, Brushed Gold Finished

A P-trap is a type of plumbing fixture that is used to route the waste water from your sink or bathtub. This pipe bends in such a way as to create a pocket of water with an incredibly important purpose. It works to prevent noxious, smelly sewer gases (like methane) from entering your home by blocking its passage through the pipe.

It connects directly to the drain beneath your sink, helping to ensure proper drainage and prevent unwanted backups or overflows. The P-trap is designed in this way because of the way that water flows through it. The curved trap portion creates a siphon effect, which helps to pull water downwards and away from your sink or bathtub.

Different Parts of P-Trap

different parts of p-trap

To connect the P-trap to your sink or bathtub, you must first familiarize yourself with its several components. Primarily, there is the horizontal pipe portion which connects directly to the drain beneath your fixture and ensures that water flows properly and does not come back up through it.

Then comes the trap portion, which is the curved section of the P-trap that creates a siphon effect, which helps to pull water downwards and away from your sink or bathtub. An elbow joint accompanies this segment and attaches it to the horizontal pipe on one end while connecting with the trap part of the P-trap at another. It helps to secure the horizontal pipe in place and keep it from moving around.

How To Connect P-Trap To Wall Drain

Orhemus Brass Round Bottle P Trap, Basin Sink Waste Trap Drain Tube Kit Adjustable Height, Brushed Gold Finished

While P-traps are relatively simple in design, they can be a bit tricky to connect properly. Follow these steps to ensure that your P-trap is connected correctly and securely so that you can rest easy knowing that your sink or bathtub will drain properly from now on.

Tools and Materials Needed

To complete this project, you will need a hacksaw, p-trap, tailpiece, wall drain fitting, and slip nuts. You will also need to ensure that your drain is aligned correctly and that you have sloped the trap arm ¼ inch per foot.


  • To begin, attach the short side of the p-trap to the tailpiece that is connected to the sink drain. Ensure your drain is completely aligned by taking the necessary time to adjust its height accordingly.
  • If you find that the trap arm is unable to be moved upward on the tailpiece any further, use a hacksaw to make necessary cuts. The trap should be placed directly underneath the drain to ensure its efficiency. This is not only to verify that it’s functioning properly but also because gravity will assist in forcing the water out more effectively this way.
  • For correct installation, the trap arm must be sloped ¼ inch per foot and aligned horizontally with your p-trap. To attach it properly, disassemble its lower portion and insert the trap arm into a wall drain fitting as profoundly as possible.
  • Then carefully remove it from this front fixture until the U-shaped section of your p-trap perfectly lines up with it.
  • To trim the trap arm to the correct size, use a hacksaw. Place it back into place and secure it with a slip nut, being careful not to tighten it too much.
  • When you have securely connected all of your trap parts in place, then it’s time to tighten up those slip nuts on both wall drain fittings and tailpiece tightly! Finally, you are finished constructing your new plumbing fixture.

Frequently Asked Questions

What happens if the P-trap is too deep?

The P-trap is designed to sit below the level of your drain in order to create a siphon that helps to push water out of your sink or bathtub. If the trap is too deep, water passes through it quickly, resulting in siphoning off the trap seal and an accumulation of sludge. This sink has a drain connection that’s located higher on the wall than code regulations allow, creating a 9-inch-deep trap seal – 5 inches more than allowed.

What happens if P-trap is backward?

If your P-trap is backward, then the water may not flow out of your sink or bathtub properly. This can be caused by a number of different issues, such as improperly fitting connections or a faulty drain pipe. If you suspect that your P-trap is not functioning correctly, consult a professional plumber for help.

How far should the drain go into P-trap?

The International Residential Code states that the highest permissible distance between a sink drain and the entrance of its p-trap should never exceed 24 inches. The drain should be inserted into the P-trap as far as it will go. This will help to ensure an effective siphon effect that is glowing all top.

Can the P-trap be higher than the wall drain?

No, your P-trap should be placed directly underneath the drain so that gravity can help to push water out. Depending on the placement of your drain and the size of your P-trap, you may need to trim the trap arm to achieve the optimal height. If you are unsure about how to properly install your P-trap, consult a professional plumber for guidance.


Want to keep more money in your pocket? Installing a P-trap is the perfect project for you. By putting forth a little bit of effort and equipping yourself with the right tools, you can successfully install this plumbing device on your own. Not only will it save time and hassle but it also guarantee optimal water flow and drainage when connected correctly.

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