How to Install a Rear Outlet Toilet


Installing a rear outlet toilet can certainly enhance your bathroom's aesthetic and functionality. This guide will provide a step-by-step approach on rear outlet toilet installation, but we recommend consulting professional help if you are unfamiliar with installing bathroom fixtures.

How to install a rear outlet toilet - Waycross Two-Piece European Rear Outlet Toilet

Tools and Materials


  • Adjustable Wrench

  • Level

  • Hacksaw

  • Drill

  • Pencil

  • PVC or ABS Glue

Rear outlet toilet installation tools & materials - adjustable wrench, level, hacksaw, drill, pencil, PVC or ABS glue

Steps to Install a Rear Outlet Toilet


STEP 1

Shut off the water supply lines where the new toilet is being installed.

rear outlet toilet installation step 1 - shut off water supply lines where the new toilet is being installed

STEP 2

If your toilet is one piece only, move on to the next step.

If you are installing a two-piece toilet, slide the tank bolts through the mounting holes on the top of the base of the toilet and thread the washers and nuts onto the tank bolts.

Verify that the tank is level and alternately tighten the washers and nuts until the tank is resting firmly on the bowl.

Rear outlet toilet installation step 2 - slide the tank bolts through the mounting holes on the top of the base of the toilet

STEP 3

Place the toilet in the location where it will be installed.

STEP 4

Measure the distance from the back of the waste outlet on the toilet to the wall hub fitting to determine the length of the P-trap connector. The connector should extend approximately 1-1/2" into the hub fitting.

STEP 5

Trim the P-trap adapter with a hacksaw to the appropriate length as necessary.

Rear outlet toilet installation steps 3 & 4 - measure distance from back of waste outlet to the wall to determine P-trap length

STEP 6

Mark the location of the pre-drilled mounting holes using the holes in the base of the toilet as a template.

STEP 7

Remove the toilet from the work area and drill mounting holes in the locations designated in the previous step.

rear drain toilet installation step 6 & 7 - mark the location of the pre-drilled mounting holes and drill the marked holes

STEP 8

Apply PVC or ABS glue around the P-trap connector and place inside the hub fitting.

STEP 9

Slide the toilet into place and press the waste outlet into the P-trap connector.

rear drain toilet installation steps 8 & 9 - apply PVC or ABS glue around P-trap connector, place inside hub fitting

STEP 10

Once the toilet is securely in place, insert anchor bolts and washers through the mounting holes in the base of the toilet and tighten into the pre-drilled holes created in step 7.

STEP 11

Place caps over the anchor bolts on the base of the toilet.

Rear drain toilet installation steps 10 & 11 - insert bolts & washers through mounting holes, tighten, place caps over them

STEP 12

Connect the water supply tubes at the bottom of the tank. Turn on the water supply and flush the toilet several times to check for any leaks around the back or base.

Rear outlet toilet plumbing diagram with the water supply tubes connected to the bottom of the toilet tank

STEP 13

Attach the toilet seat by placing it on top of the bowl and securing it in place with supplied bolts.

Rear outlet toilet installation step 13 - attach the toilet seat by placing it on top of the bowl and secure with bolts

STEP 14

Finish your installation by applying latex caulk or tile grout around the base of the toilet. This will finish the joint between your floor and toilet bowl and divert water away from the base of the toilet.

Rear outlet toilet installation step 14 - apply latex caulk or tile grout around the base of the toilet

Installation FAQs

What is the rough in height for a rear discharge toilet?

The standard rough in height for a rear discharge toilet, or rear drain toilet, is typically about 4” from the floor to the center of the outlet pipe.

Does the outlet size matter on a toilet?

Typically, larger outlet sizes will improve the overall performance of a toilet, make sure to measure your system to ensure the largest possible outlet can be installed.

What is the difference between a back entry and bottom entry toilet?

The main difference will be where the water supply connection is located. For bottom entry toilets, the water line connects to the cistern near the base. For back-entry toilets, it is hidden from view and connected directly from the back of the cistern.

Will this require bidet outlet?

No, rear outlet toilets don’t typically require a bidet outlet but there are bidets available that are specifically designed for rear outlet toilets.

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