P Trap S Trap Toilet

Firstly let’s understand what is trap. Trap is a bend in the pipe where the waste goes out of the toilet. It retains some water after flushing causing a seal and preventing sewer gases from entering the building. There are 2 types of trap S-Trap & P-trap.

When asked to a Plumber, what type of trap is best for wall mounted and floor mounted commode/toilet, this is what he shared…

Usually the traps are inbuilt and provided by the builder. These traps are concealed. Usually the builder decides the trap on
(1) what type of toilet will be installed and
(2) the space availability.

For a wall mounted toilet/commode P-Trap pipe needs to be fitted and for floor mounted S-trap pipe is fitted.

P-trap pipe is designed to outlet through the wall whereas S-trap is designed to outlet through the floor. Therefore S-trap pipe is not suitable for wall mounted toilets.

Most builders provide with P-trap wall mounted toilets these days.
But if there’s S-trap pipe fitted by the builder and a home owner wants wall mounted toilet, than the fitting needs to be changed. This can be done by any plumber. For changing the trap type, an additional line if taken from outside the building and the trap fitting is changed. But for this, society and builder permission is must. Not many builders do object for fitting and additional line on outside building wall. But there are few big builders who do not grant permission as they do not want to hamper the look of the building. In this case the line is fitted from inside (concealed). But here there can be choke-up problems. To avoid choking problems in society, builder usually doesn’t object on outside additional line.

About the Author:

Hi! This is Nitin, founder of ContractorBhai.com. We provide Affordable 3D Interior Design Service


  1. ajit 20 January 2016 at 12:31 pm - Reply

    For Johnson make Floor mounted S trap commode what is the distance from wall for the outlet in floor if in case I need to replace with some other make commode. could you pl tell.

    • contractorbhai 21 January 2016 at 1:53 pm - Reply

      every product comes with detail specifications. there is no one answer for all product range

  2. mann 23 March 2017 at 8:17 pm - Reply

    Do all Indian toilets have traps? Even the Indian ones which are not elevated (i.e. right on the floor)?

  3. NASIR ALI 17 November 2017 at 9:36 am - Reply

    now the comeouts comes with built in ‘S trap and p trap which is better ‘S’ trap or ‘P’ trap ??


    • contractorbhai 17 November 2017 at 10:57 am - Reply

      instead sir these decision is more driven on basis of whether you want wall mounted WC or not !? Wall mounted WCs are in trend because they look modern, cleaning is easy, saves space. It goes with P Trap. So P Trap is preferred in most cases.

  4. Nithin 24 October 2018 at 8:59 am - Reply

    I have a Floor Mount WC, and it had a P Trap outlet. I am changing my WC now, The flooring has been made according to the Floor Mount. What do I do now.
    1) Will I get WC with Floor Mount and P Trap (single unit Water Closet with Cistern)?

    • contractorbhai 29 October 2018 at 10:51 am - Reply

      Please have a expert plumber to make final decision. It is very important to make this change correctly, else it will lead in to water leakages problems.

  5. Dibo bandhu biswas 25 January 2019 at 1:11 am - Reply

    Hindware megma two set floor mounted p trap commode are avaible ?

  6. subhash t. 7 March 2019 at 5:56 pm - Reply

    Good information.

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