Difference Between an S-Trap and P-Trap Toilet Bowl

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Since the toilet is frequently used daily, most homeowners try to ensure to install a toilet bowl that is of good quality – which is why they usually opt for the best toilet bowl brands. Typically, older homes have an s-trap toilet bowl installed, while newer homes have a p-trap toilet bowl.

Homeowners want to find out the difference between an s-trap and p-trap toilets so they will know which is a better fit for their household needs. Some of the main features and benefits of a toilet bowl trap and their differences are described below.


Functions Of A Toilet Bowl Trap

The toilet bowl as well as other parts of the plumbing system in a home like the sinks and tubs are connected to the sewerage system. The waste in the sewerage system usually decays due to bacteria and other harmful microbes producing various gases like hydrogen sulfide, methane, carbon monoxide, and ammonia.

If the toilet bowl is connected directly to the sewerage system the unpleasant smell of these gases will fill the home, making it difficult for the homeowners. Hence, toilet bowls always have a trap through which it is connected to the sewerage system.

Knowing your toilet bowl trap is important to avoid mistakes when getting a new toilet bowl. Traps usually are filled with water, to prevent harmful gases from entering the house. If the toilet is not used for a long time, the water in the trap may evaporate, and the gases may enter the home.


S-trap Toilet Bowl


Most of the older homes in Singapore have an S-trap toilet bowl. If you are wondering what this looks like, it is an S-shaped trap between the toilet outlet and the sewer system. This is usually filled with water. This S-trap toilet like the Baron W-203A has the simplest design and is suitable for homes where the toilet bowl is connected to the drainpipe through the floor.

An advantage of having this trap is that if larger items will accidentally fall in the toilet, they will remain in the S-trap. Somehow, families with babies and young children may find this feature of the S-trap useful.


P-trap Toilet Bowl


Sometimes, property owners are away from their homes for several months and toilets are left unused. The water in the S-trap may evaporate and toxic gases might leak into the house.

Now, to overcome this problem, changes in the plumbing guidelines were done and new homes have P-trap toilet bowls (e.g., Baron W-888 or Saniton Camellia ST2488-SC3033) now. The P-trap toilet bowl is shaped like the letter P and is usually connected to the drainage system through an opening in the wall.


Dry Traps Can Be More Than Just Smelly


One common toilet bowl problem is its unwanted smell. The foul smells from the toilet are caused by hydrogen sulfide, ammonia, methane and are the most obvious indication that the toilet trap is dry. However, there are other far more harmful gases like carbon monoxide, an odorless gas that can also enter the house if the toilet trap is dry. Inhaling these gases can be fatal in some cases.

Additionally, disease-causing pests like rats, mice, and cockroaches can enter the house through the toilet when there is no water in the trap to block their entry.



Knowing which type of trap to install is one of the things to note before replacing your toilet bowl. One of the trap’s important functions is to prevent harmful gases from coming out of the toilet bowl. This is important because inhaling these gases can be fatal to homeowners. The water in the trap keeps these gases from running out of the toilet.

When the toilet has not been used for a long time, water inside the traps evaporates. Therefore, what is the difference between these two traps? An S-trap is an S-shaped trap between the toilet outlet and the sewer system. It is connected to the drainpipe through the floor.

On the other hand, a P-trap is shaped like the letter P and is connected to the drainage system through an opening in the wall. It can be a lot of work understanding and doing this alone, which is why it is beneficial to hire a professional for your toilet bowl installation.


At Toilet Bowl City Singapore, we understand the need to keep home service expenses within your budget. Hence, we offer honest and reasonable pricing for any of your toilet bowl installations works. Select from our range of toilet bowl brands, browse our past toilet bowl installation projects for inspiration, or read up on toilet bowl-related articles to find out more about toilet bowl installation services. Get in touch with us now via WhatsApp at +65 8241 0032 or email us at enquiry@toiletbowlcity.com!