How to Install a Toilet From Scratch

Installing a toilet from scratch isn't the impossible task that it might seem. First of all, there's no electricity involved, keeping it comparatively simple. Secondly, there are only two connections you need to make: one from the water supply to the tank, and the other from the bowl to the sewer inlet, also called the toilet flange or closet flange. The job doesn't require any special tools, and it's a good project for a first time DIYer.

Installing a toilet from scratch isn't as hard as it sounds.
  1. Clean off the toilet flange. Ensure that any construction materials, such as plaster and grout aren't present on the flange. This will help ensure a good seal. Scrape these away with a putty knife. Clean off the flange with a rag and standard bathroom cleaner. Insert the flange bolts, with the threads pointing upward, into the flange. Position them so that when you look at the flange from above, they are positioned at 9 o'clock and 3 o'clock.

  2. Turn the toilet bowl over. Rub out a thin bead of plumber's putty and press it along the rim of the bottom of the toilet. Align the wax ring so that it encircles the exit in the bottom of the toilet and press into place.

  3. Turn the bowl so that it is right side up again. If this is a heavy bowl, have an assistant help you with this step. Lower the bowl over the flange. Ensure that the flange bolts are threaded through the holes in the bottom of the bowl. While you do this, you also need to make sure that the outlet on the bottom of the bowl where you attached the wax ring lines up with the closet flange in the floor. Once this is all set, lower the bowl to the ground. Press it in place to seal the wax and the putty.

  4. Slip the plastic and metal washers over the flange bolts. Tighten the flange nuts by hand. Then tighten each nut, one side at a time, an additional 2 or 3 turns.

  5. Place the tank on the back of the bowl, first aligning the cone gasket in the bottom of the tank so that it fits into the inlet on the back of the bowl. Thread the tank bolts and washers through the bottom of the tank. Tighten the tank nuts from below.

  6. Wrap the threads on the water supply valve and the tank inlet with plumber's tape (this helps prevent leaks). Attach the metal end of the water supply hose to the valve and the other end to the tank inlet. Tighten the couplings with pliers.

  7. Turn on the water supply and allow the tank to fill until it stops. Flush the tank. Check for leaks. Tighten any couplings or nuts if necessary.


  • Do not overtighten any of the nuts on the toilet, as this could crack the porcelain.
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