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P Trap Vs S Trap: Which One’s The Best?

P-traps came into the market later than s-traps. But they seriously impacted the factor- ease of use. But are p-traps better than s-traps? Or is it the opposite?

P trap vs S trap, which one drains better?

P-traps are newer and so have a design advantage. P-traps are suitable for installation on top floors whereas s-traps are suitable for ground floors. P-traps are consistent in maintaining water traps while s-traps have a tendency to dry out. S-traps, however, have an additional air-filter feature.

This is only the beginning of our discussion. There’s still a lot to understand before you set up any of these traps.

So, let’s get started!

P Trap vs S Trap: Quick Review

Don’t worry if you’re in a hurry. You can use this fast analysis to acquire a better understanding of the entire comparison.

FeaturesP TrapS Trap
InstallationComparatively easyComparatively hard
Suitable SetupSuitable for top floors.Suitable for ground floors.
Design AdvantageOvercomes problemsOutdated
EfficiencyMore efficientLess efficient
Backflow PreventionIneffectualClinical 

You now understand the basic characteristics of these two traps. However, we advise you not to make a decision immediately.

P Trap Vs S Trap: Head To Head Comparison

Picking between traps isn’t that easy. But don’t worry. Our analysis will help you make the perfect decision for your home. So, without further ado, let’s get started.

The following is a head-to-head analysis based on a few associated factors-


A P-trap is simple to install and inexpensive. If you have the time, you can do it yourself.

There can be different types of PVC connections. So, to install the p-trap, you must have the necessary PVC couplings. This includes a pipe tee, elbow, compression nut, and wrench. 

To make it easy for you to find PVC connections, we’ve picked some for you online:


Once you have gathered all your supplies together it should be easier to install your new p-trap.

P-traps are designed to be in a sink or bathtub drain. The p-trap is usually made by drilling out a hole in the floor drain. Then followed by attaching it to the drain.

Normally s-traps are used in ground floor installations so they can be done below ground level. Normally they are installed with PVC glue. But there are also ways of joining pipes without glue.

Is installing S-trap hard? The answer is, well, yes. Installing an S-trap is passed down in the trade along with other secrets. It’s said that only the plumber knows about them.

We think that p-traps are much easier to install than s-traps. Whereas in the case of s-traps, you can mess things up if not supervised by any professional.

Design Advantage

In a P-trap design, instead of looping over and back down, it’s slightly different. It enters a horizontal run before exiting downward. The horizontal run directs the water into a 90° turn and forces it to move downward. 

This type of design is more common than the looping one. Because this design has a larger path for the water. As a result, the trap is better able to manage large amounts of water.

An s-trap has a straightforward design. The drainpipe drops down from the sink and into a traditional trap. The drain likewise comes down from the sink and into the trap.

There’s a problem with this design. Most people have a habit of dropping potential items down the sink. Which ends up blocking the drain.

You can avoid this particular problem by doing one simple thing: adding an overflow pipe. Through this, you can actually turn an s-trap into a p-trap.

We think p-traps give you more design advantages than s-traps. Because S-traps seem to become quite outdated in this field.


P-traps are fairly effective and consistent in maintaining water traps. Cylinders with four rows and cylinders with five rows are fairly comparable. This is in terms of the amount of water they receive.

This is not the case for size. Because of the expense in manufacturing a larger capacity cylinder as compared to a smaller one. 

When it comes to p-trap design, larger diameter pipes tend to be more efficient at catching water.

S-traps are less effective as they have a tendency of drying out. This allows the flow of gases. They are also much harder to keep clean. You need to replace the entire trap system which can be costly. 

Bacteria can build up in the s-trap, causing odor and comfort issues.

P-traps are the winners for efficiency. Unlike S-traps, they are dependable when it comes to keeping water traps in place.

Backflow Prevention

The P-trap functions by establishing a natural water seal. Water can flow into the overflow pipe, but not back into the sink. The water seal in the bottom of the trap prevents backflow. This prevents sewer gas from entering the trap.

You should know that an s-trap has an air filter if you have one. It prevents sewer gases from backflow into your home without getting rid of sewer gas completely. 

Our winner for this criteria is the s-traps. They have an advanced air filter. So, it overcomes the gas leak problem of p-traps.

P Trap Vs S Trap: Final Verdict

We guess that we have learned more or less about all the factors between the two traps. And we can get to the conclusion that p-traps are more appropriate for you right now. 

They are easier to install, advanced in design, and more efficient. Although s-traps overcome its backflow prevention factor, in comparison, p-traps are better.

Aside from these considerations, the cost and durability of these two products are almost indistinguishable. The drains can still be jammed but there are many ways to prevent clogged drains. 

We hope we could make all the factors crystal-clear to you. So, you can make the ideal decision.


Question: Why does my p-trap smell?

Answer: Your p-traps are meant to retain water and create a seal. This prevents the entry of sewage gases into the bathroom. If the P-trap isn’t operating properly, sewer gases might seep into the bathroom. This can make your sink smell bad.

Question: Does my p-trap need a vent?

Answer: Yes, all traps need vents to them in all cases. Without a vent, the water seal in the trap is sucked out. This allows sewer gases to enter the room.

Question: How far should the vent be from the p-trap?

Answer: The distance between the trap’s weir and the vent pipe aperture must not exceed 30 inches. This is if the fixture calls for a 1 ¼ -inch trap.

Summing Up

We hope that this clears your confusion about P trap vs S trap. If you’ve read this far, you’ve found all of the answers you’re looking for. Always remember to keep your traps clean. 

You must now be able to make your choice. Please let us know if we were able to assist you in making your decision.

Best wishes!