When it comes to plumbing, S trap and P trap are two commonly used types of traps. They are designed to prevent sewer gases and odors from coming back into your home or business. While they may look similar, there are some key differences between the two.
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What is a Trap?
Before we dive into the differences between S trap and P trap, let’s first define what a trap is. A trap is a U-shaped pipe that is installed under a sink, shower, bathtub, or any other plumbing fixture. Its primary function is to hold a small amount of water, which creates a seal that prevents sewer gases and odors from coming back into the room.

What is an S Trap?
An S trap is a plumbing trap that is shaped like the letter “S.” It is designed to be used when the waste pipe is located behind the wall, and the fixture is mounted to the floor. The waste pipe will come down from the wall and connect to the bottom of the trap, which then connects to the fixture’s drain.
One of the main issues with S traps is that they can easily become dry, which can break the seal and allow sewer gases to enter the room. This is because the water that is trapped in the U-shaped bend can be siphoned out if there is not enough water flowing through the trap. In addition, some building codes prohibit the use of S traps because they are more prone to clogs and can be difficult to clean.

What is a P Trap?
A P trap is a plumbing trap that is shaped like the letter “P.” It is designed to be used when the waste pipe is located below the fixture. The waste pipe will connect to the bottom of the trap, which then connects to the fixture’s drain. The top of the trap will connect to a vent pipe that allows air to flow through the system, which helps to maintain the water seal.
P traps are less prone to clogs and are easier to clean than S traps. They also tend to hold water better, which means they are less likely to dry out and break the seal. Because of these advantages, P traps are the more commonly used type of trap.
S Trap vs P Trap:Which One Should You Choose?
If you are building or remodeling a home or business, it is always best to consult with a licensed plumber to determine which type of trap is best for your specific situation. In general, P traps are the safer and more reliable option, but there may be instances where an S trap is necessary.

S traps and P traps are two types of plumbing traps that are used to prevent sewer gases and odors from entering your home or business. While S traps are shaped like the letter “S” and are designed for use when the waste pipe is located behind the wall, P traps are shaped like the letter “P” and are designed for use when the waste pipe is located below the fixture. P traps are generally the safer and more reliable option, but it’s always best to consult with a licensed plumber to determine which type of trap is best for your specific situation.