Bathroom plumbing fixture,sanitary ware installation

How to Install a Toilet

Plumbing for Your Toilet

Here we offer general instructions and precautions for roughing in, as well as installation procedures for tying into your present drain waste vent and supply systems. When all the roughing in has been completed and you are ready to assemble your toilet, your rough plumbing should resemble that shown here.

Most Common Mistakes

  • Violating or ignoring local code restrictions.
  • Using pipes that are too small.
  • Attaching copper to galvanized without using a brass or dielectric fitting between the two.
  • Not using PTFE tape or pipe compound at threaded joints.
  • Not leveling your fixtures when installing them.
  • Not installing an air gap filling for fixtures.
  • Cutting supply stub outs too short to install the shutoff valves onto after the finished wall is in place, or
  • Not properly aligning tubing into fittings or stop valves. (Forcing the nut onto the compression ring at an angle when the tubing is at an angle will cause a leak.)
  • When turning the water back on in your home, always run the outside hose valve or flush your toilets to bleed dirt and air from the lines. This debris can cause problems in your sink faucets and other plumbing trim.

Installing Your Toilet

Pipes required include a cold water supply stub out with a shutoff valve, flexible tubing for above the valve, and possibly one air chamber.

This is possibly the single, most troublesome fixture to install as it requires its own 2" minimum vent and a drain of at least 3" in diameter. If the toilet is situated on a branch drain, it cannot be upstream from the sink or shower. The minimum side distance allowed from the center of the toilet bowl to a wall is 15 inches, and 12 inches from the center of the bowl to a bathtub; clearance from the front of a bowl to a wall or fixture should be 21 inches.

1. The closet bend and toilet floor flange must be roughed in first. When replacing a toilet, you will need to scrape up the old wax gasket. A putty knife works well for this. Remove the old bolts from the floor flange and scrape the flange clean to prevent leaks at the base of the new bowl. If the old flange is cracked or broken, replace it with a new floor flange.

2. Position the floor flange so that the underside of the flange is at the level of the finished floor. (It is always best to install the finished floor so that it runs underneath the toilet.) You may need to use a piece of finished flooring material if the floor has not yet been installed. Now you can finish tightening the screws that hold the floor flange to the floor. Put a small level on the flange while tightening to be sure it is level.

3. Set the new floor bolts in plumber's putty and insert them through the flange, adjusting the bolts so they line up with the center of the drainpipe.

4. With the new toilet bowl turned upside down, position the new wax gasket over the toilet horn on the bottom of the bowl.

5. Apply plumber's putty around the entire bottom edge of the bowl.

6. Using the bolts as guides, lower the bowl into place over the flange. Press down firmly while giving a slight twist. It is important that you feel the toilet being pushed into the wax ring. If you do not feel this, the flange is set too low and you will not get a good wax seal between the flange and the horn (waste outlet). Also, if the wax ring is cold, it will not properly seat. You may need to warm it in the sun for awhile until it is pliable.

7. Use a level to level the bowl, adding shims where necessary. Also be sure the toilet is square and aligned with the wall. Then tighten the nuts and washers onto the bolts by hand.

8. Place the rubber tank cushion (if one is needed) into position on the rear of the bowl and fit the rubber gasket onto the flush valve opening on the bottom of the tank.

9. Position the tank over the bowl; then tighten the nuts and washers onto the mounting bolts..

10. Tighten the hold-down bolts at the base of the bowl with an adjustable wrench. Use your level to assure the bowl is still level.

11. Fill the decorative caps with plumber's putty and place them over the bolt ends. Seal the base of the toilet bowl with plumber's putty or silicone caulk.

12. Cut the end of your supply line stub out and attach a shut off valve. Then, connect the shutoff valve to the flexible tubing and connect the tubing to the bottom of the tank, where you will find a supply stub out.

Custom Search


All contents of this page are taken from