What is a p-trap under a sink? (THIS Is Essential!)

A p-trap is a plumbing fixture that traps sewer gasses and liquids so they can’t escape. It is typically found under every sink, washing machine, and dishwasher.

They are thus present in bathrooms, laundry rooms, and kitchens. They are often also built into toilets. Some of the water that is flushed remains in the p-trap. This stops dirty water and sewer gases. The latter can smell terribly or even be dangerous. This is why every sink needs one.


How does p traps work?

It is typically made out of a range of materials such as PVC, PP, ABS, stainless steel, or PE. These are types of plastics. They typically come in two heights: 6 inches (152 millimeters) and 10 inches (254 millimeters).  The height of the p-trap can be chosen based on the type of fixture they would like it to be installed in. P-traps are typically found in white or light-colored plastics, which will match with a variety of fixtures.

Dirt can get stuck in a P-trap and this can lead to clogs. This can slow the flow of the water or even stop it. If your sink is not draining properly and using a plunger didn’t work, you can check the P-trap. In some instances, there is a plastic piece that can be unscrewed. This allows you to get some dirt out of it. In other instances, you will have to remove the P-trap.

This is generally done by turning on the connectors. Have a bucket nearby as there is some water in the P-trap. It is possible that the problem is farther in your system. It is possible that you will need a camera to check what is going on. You can also try to add an attachment to your pressure washer and insert this into your pipes to push away clogs. 

 P-Traps vs S-traps: conversion kits

The letter P refers to the shape of the trap. In the past, people used S-traps as well but these don’t work that well so should be avoided. A lot of plumbers will replace S-traps when they run into one. P-traps function better as they are more stable and better at retaining water.

You will often notice when you have a poorly functioning trap as it will smell bad in that room. Therefore it is often not that urgent to replace the traps if there are no big issues. In states where an S-trap is a code violation, you might look into it further. Especially if you want to sell the house. Home inspectors might note this down and mention it in their report.

There are conversion kits that make it easy to convert an outdated S-trap to a modern P-trap. In essence, this is a piece of plastic that makes it easy to install the P-trap. We have outlined how to install a P-trap in a small space here. In general, it is quite easy to convert to a P-trap as you just have to connect some pieces of pipe. Just be careful that you don’t damage the drain in the wall!

 P-Traps vs bottle trap for sink

Sometimes there is just not enough space for a P-trap. This can be the case for a sink in a small toilet or utility room. Bottle traps are then used. They function quite similarly to P-traps but are smaller. These function really well and are installed in a lot of places. They are often made out of stainless steel whereas P-traps are often made out of plastics. This can make the bottle traps more expensive than standard P-traps. 

Example of a bottle trap. These are mainly used in smaller rooms such as toilets. Copyright reserved by Plumbinginstantfix

P-traps can also run dry when you haven’t used a sink for a while. This can lead to a nasty smell. Just let some water flow for 5 minutes and the p-trap should be filled again. The nasty smell should be gone quite soon after this as well. The new water fills the P-trap again and you are good to go.

If the plumbing system is not properly vented, your p-trap can get sucked empty or your sink can overflow. Residential homes therefore often have a ventilation system that goes through the roof or is installed in the attic.

This is a piece that is installed on top of the main drainpipe (where several drains come together). Especially in taller buildings, it is necessary to vent the plumbing system and secondary ventilation might be needed to make sure that everything works properly.

How to repair a P-trap

First, you should look under the sink at the inlet and outlet on the trap and see if there is water damage. Next, check for leaks around the outlet by turning your sink faucet on.

If you notice that there are problems with the connectors, you can try to tighten them again by turning them. Don’t overtighten them though as they can break if you put too much pressure on them. 

If they’re still leaking after this, then that means that one of your seals has broken or deteriorated and needs to be replaced or sealed with some plumber’s putty. It is also possible that there is a crack in the P-trap (for example due to cold). It is often easier to install a new P-trap if you notice that yours is quite old or is starting to leak. Let’s take a look at how this is done. 

Most hardware stores have P-trap kits. These are generally made out of plastic and quite cheap. Just connect the different parts. You might have to adjust the drain as well though if the new P-trap doesn’t line up with the drain.

Repairing a P-trap is often quite easy as you can just replace it with a new one.

How to Install a P-Traps

Each p-trap is different, so you need to know what size of p-trap you have before you can install it. Also, take a look at what material is being used (plastic or stainless steel). Generally, this is a quite straightforward process as you just have to turn the connectors. You might have to change the directions of some parts to get it in place.

As long as you have a good quality P-trap, the installation should be quite straightforward. P-traps are quite cheap in general. More expensive models use better connectors and rubber parts. A good P-trap should last about 10 years so you shouldn’t have to replace it too often. 

 It is essential that you don’t drop dirt, hair, crumbs, or cooking fat in your sink. This can clog or even break your P-trap. It is quite easy to remove the P–trap but it is annoying to do. Furthermore, it can build up clogs farther away in your system that is harder to reach. Especially hot liquids should be avoided as these can break the P-trap. We have to remember that this is made out of plastic and heat can deform it. 

P-traps are commonly found on plumbing fixtures in your house. They are found under your sink. They contain water to stop sewer gasses and dirty water from coming in. The p-trap contains two plugs – one for each direction – that are raised whenever water is flowing through it to do this.  

P-traps are essential for every sink. They make sure that bad odors don’t enter the house. They also make sure that dirty water doesn’t flow back inside the house.