What is the P-trap of a toilet and where is it located?

What is a p trap toilet?

A P-trap toilet is one that has a p-shaped trapway that removes the waste through this channel. The toilet segment is used mainly for lavatories, sinks, and bathtubs to evacuate waste and liquids to the septic tank. The P-traps reserve a tiny amount of water that prevents the foul smell of the sewer gases. But if the trap pipe gets clogged, then it will emit bad odors from the pipe. Also, if the traps are not that much longer or bent a little bit, it will cause a bad odor. P-traps were built in a way that could eliminate the main plumbing issues where S-traps tend to siphon away too much waste water.P-Trap toilet

Do all toilets have P traps?

The trapways are the maximum widened channel that passes the waste materials to the drainage pipe, and then it sweeps those wastes to the septic tank of the system. Not all toilets need to have a p trap; that trapway may be of other different shapes. There is a point notable that Toilets have their own built-in traps, and so do floor drains. So if there could be no p trap in some toilets, there are always built-in toilet trapways in every toilet. 

Where is the P-Trap in a toilet?

The P-trap is the particular channel between the toilet bowl and the drain pipe, and the waste goes through this channel. It looks like a U-shaped channel that holds some amount of water. The particular amount of water acts as the barrier between the sewer gas and the toilet, and it prevents the outcoming of these toxic gasses in the bathroom ambiance. 

What is the standard toilet P-Trap size?

There are tons of sizes available for the p trap. But according to the manufacturer and experts, the optimum size of a p trap is 1 to 1/4 inch for a standard size toilet, but the size may vary in the case of the kitchen or shower trapways. standard toilet P-Trap

How does a toilet P-Trap work?

The toilets must have trapways that should be p traps or any other kind of traps. The p traps work like a combined two 90-degree joints with a horizontal overflow pipe. The main duty of the p traps is detaining the noxious gasses and their smells. If there were no p traps, then the foul smell may have burst into the toilet ambiance. So all toilets need p traps to capture the bad smells out of the toilet.

How to clean and unclog a P-Trap toilet?

There are thousands of ways of cleaning a p trap toilet, but for that, you need to have some toilet cleaning gadgets like a plunger, a snake, or an auger. Here I will demonstrate the ways of cleaning the p trap toilet.

By using the plunger


  • First, take a beehive plunger or a normal type of plunger and apply that to the entrance of the trapways and seal around the cup when it is placed over the hole.
  • After placing the plunger into the toilet bowl, create an angle and create a tight vacuum seal so that the suction process works strongly. The vigorous plunging action forces water in every direction it can go and performs the push-pull motion so that it can eliminate the clog in the p trap.
  • Plunge several times and then pour a big bucket of water into the toilet. And flush several times. After a while, all the dirt will be removed from the p trap. 

By using the augerusing-the-auger

  • Take a long and sturdy snake or auger. Then insert the auger into the trapways. Then extend the cable of the auger. Keep cranking the cable and pushing it hard until the handle contacts the tube inside the p trap. When you find something is impeding the auger from moving forward, it is probably a chunk of waste. 
  • Try to break the chunk of waste by moving the auger forward and backward. Then slowly pull over the wire of the auger.
  • Perform flush several times. In the meantime, all the blocks and clogs might be removed from the trapways.

How to remove toilet P-Trap smell?

The main reason for this acute smell from the p-trap is lacking water in the water storing and trapping section of the structure. The p-trap may get dry, especially in winter, and the foul smell comes or travels through the p-trap and disseminates throughout the bathroom. 

To remove the smell from the p-trap, you need to apply a lot of water to the toilet. Apply a gallon of water and flush the toilet several times. This amount of water will be restored in the catchment area and will work as an obstruction in the section between the trapway and the toilet.

How to install a P-Trap toilet?

The installation of the p trap toilet is assumed as an arduous job, but it is actually not that difficult if you know the actual process of installing the p trap. Here I will try to depict the elaborate process of installing a p-trap toilet.

  • First, implement the waste pipe to the back end of the pan collar. There must be a considerable distance between the toilet and the finished wall.
  • In the next step, put off the plastic cover and rubber from the interior section of the connector. Then split the frontier segment of the pan connector down. Make sure that the separated section is even and straight. Then apply some lubrication to the rubber and the plastic cap so that the waste can go through its path smoothly.
  • Ensure that the inlet hose pipe is connected to the hole on both sides of the toilet. Connect and push the fully assembled pan along with the cistern back to the wall.
  • Then check for the leaks inside the trapways. If the p trap gets dry, then it will produce foul smells. So apply a huge amount of water after installing the p-trap.

Do RV toilets have P traps?

Most of the RV toilets do not have p traps as there are some valid reasons behind this, like, RV toilets

  • One of the main reasons why RVs don’t apply P Traps is that there should be some amount of water present in the bending section so that it can work seamlessly. But during the summer, water can quickly evaporate and make it dry as a resulting odor comes from the storage tank and pollutes the entire bathroom ambiance. 
  • In the winter months and in the cold weather, the water turns into a freeze and blocks the entire area of the bending section and outside of the vent pipe. A lot of foreign particles like undissolved paper tissues, sanitary napkins, and other objects may clog the entire section.

Alternative of P-trap in RV toilets: As an alternative, there is a small pathway that directly links with the greywater and blackwater septic tank, eliminating the RV toilet’s foul odor.

Why P-trap toilets are better than S-trap toilets:

After researching the table above, it is a clear declaration that the p trap toilet is the clear winner. Why do we choose the p trap toilet over the s trap? 

  • The design and aesthetics of the p trap toilet are much more ahead compared to the s trap toilets. 
  • The p trap toilet is a modern invention. On the other hand, the s trap is nothing but an ancient specimen that was suitable for the older toilets. 
  • The p trap can be a great pick in eliminating the foul smell from the toilet. The S trap toilets are often denounced for making foul smells.
  • As the p trap can store some amount of water, the chance of being dried out is very much less, and on the other hand, there is no such system of storing water in the s trap, so it is evident that the foul smell will extract from it.

After analyzing all these aspects, we always recommend you to purchase a p trap toilet for your home.

Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.

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