How to Install a Toilet S-Trap

An s-trap toilet is one in which the outlet for waste passes through a pipe in the floor rather than a pipe in the wall which is called p-trap. These days p-trap toilets have become much more common, but there are still some older houses and even commercial buildings with s-trap toilets. Because of this, if you own an older home or business building, it can be important to know how to install an s-trap toilet, especially if you don't want to do some serious remodeling by adding a waste outlet pipe in the wall. This tutorial assumes you have already removed the old toilet if there was one, and cleaned up the area to ready it for the new toilet.


Step 1

Check to see if the toilet flange is above the surface of the floor or below the surface of the floor. If it is above the surface of the floor then you can use a standard-sized wax ring and john bolts. However, if the flange is below the surface of the floor, then you will need an extended wax ring and longer bolts.

Step 2

On each side, take one john bolt and slide it into the square slot and then move it over and center it.

Step 3

Line up the wax ring with the opening of the flange and then center both the wax ring and the john bolts.

Step 4

Take your toilet and line up the holes on each side with the john bolts. Once the john bolts are through the openings, then set the toilet down.

Step 5

Press straight down and put even steady pressure on the toilet. This is to ensure that seal is tight and no water or sewer gases can escape.

Step 6

Put the cap washer over the bolt and then the metal washer.

Step 7

Thread the nut onto the bolt. Tighten it with your fingers first, then carefully with your adjustable wrench. You don't want it too tight because porcelain can crack if the john bolts are secured too tightly.

Step 8

Take your small hacksaw and saw off the bolt just above the nut on each side of the toilet, otherwise your caps won't fit.

Step 9

Put the new caps over the bolts and tap them hard enough so they stay on.

Step 10

Take your flexible water line and hook it up to the fixture under the tank and then hook the other end to the water pipe coming from the wall.

Step 11

Install the toilet seat according to the instructions that came with your toilet.

Step 12

Turn the water back on and then give your toilet a few experimental flushes so you can check to be sure the seal is good and you don't have any leaks.

Step 13

Once you are sure there are no leaks then caulk around the bottom of the toilet to help with sealing it.

Regina Paul

Regina Paul has been a full-time freelance writer and author for three years. She has published over 500 articles online and 10 books. Her articles are published at Associated Content,, and The Fun Times Guide. Her books are published with Amira Press, Eternal Press, and Leap of Faith Publishing.