How to Move a Toilet Drain in Concrete – 7 Steps (with Pictures)

Written by

Paulk Webb


Freddie J. Hagopian

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how to move a toilet drain in concrete

Is your bathroom undergoing remodeling or renovation and you want to change the toilet’s position—along with the toilet drain location—to fit your interior ideas?

Normally, this will require a professional. But if you are keen on doing it yourself, this article is for you. We will teach you how to move a toilet drain in concrete, including the considerations that you must make, plus the tools and materials that you must have during the process. 

Steps in Moving a Toilet Drain

What you will need

  1. plastic sheeting (to cover fixtures, objects, and the door)
  2. jackhammer 
  3. mini shovel
  4. saw (preferably reciprocating saw)
  5. spirit level
  6. measuring tool
  7. polyethylene vapor barrier
  8. necessary pipe fittings
  9. pipe glue (depending on the type of pipe)
  10. primer
  11. sandpaper
  12. gravel and dirt (enough to cover the drain area)
  13. concrete

Before we begin, we don’t recommend moving a toilet drain in concrete by yourself if you have zero experience in plumbing or building. Hiring a licensed plumber is still the best option for this job. 

But if you like to DIY, have someone assist you. After all, this will save you some cost to move your toilet.

Step 1: Measure the Toilet Clearance


Assuming that you’ve determined where you want to relocate a toilet, you now have to measure the toilet clearance. This may differ per local building codes, but below are the usual minimum measurements required:

  1. 10, 12, or 14 inches rough-in or the distance between the wall and flange center
  2. 15 inches distance between the flange center and walls or obstacles on the sides
  3. 21 inches of space in front of the commode
  4. 18 inches distance between the toilet and another bathroom fixture

Considering the rough-in of the toilet plumbing in the concrete slab—along with other clearances—is important to ensure that the commode is aligned with the drain and will fit the place with enough space to move.

Step 2: Covering With Plastic Sheeting

You will use a jackhammer to drill the toilet drain in the concrete slab later on, so the room will have a lot of dust. 

To avoid dirtying other fixtures and objects in the area, cover them with plastic sheeting. We also recommend covering the door area to avoid dust from getting through the gaps.

Step 3: Turn off the Water Supply and Remove the Toilet


Before moving a toilet’s location, there must be no water present in the process.

  1. Turn off the main water supply for your home and the toilet’s shut-off valve. This is to prevent water from flowing through the plumbing system while you modify the pipes.
  2. Flush the toilet to empty the tank. You may manually scoop out the water left from the bowl or use sponges to drain it. 
  3. Carefully remove the toilet from the floor and place it on one side. We recommend covering it with plastic sheeting as well to avoid dirt. 
  4. When the waste pipe is exposed, crumple a paper towel or use a cloth to cover the opening. This will prevent the sewer gases from escaping. 

Step 4: Break the Concrete Floor 


Since you want to move the plumbing in the concrete slab, you have to break the floor to see how we will extend the pipes. We advise wearing a mask in this process since it will be dusty!

  • Open the floor surrounding the waste pipe at the size necessary to cover the drain extension. You should know where the toilet is going to create the appropriate trench.

We recommend renting and using a jackhammer for speed and convenience, especially if the floor is 4 inches thick or more.

However, you have to be very careful since you don’t want to drill the pipes. A sledgehammer provides you with more control but requires more strength.

  • Grab a mini shovel and take out the rocks or soil in the opening to fully expose the pipe.

Step 5: Cut the Pipe Riser Below the Floor Level


The riser is the vertical pipe connected to the horizontal one. This is also where we insert the toilet flange.

  • With a spirit level, check if the riser was inserted straight by the plumber who installed the system. This is important so the toilet will be stable as well when we put it back.
  • If the riser pipe is straight, cut a portion so you can insert new fittings. The correct way is to cut it below the floor level with enough space to insert the new pipes.

Using a reciprocating saw for this task is more convenient since it’s machine-operated, but any effective saw will be fine.

  • If the spirit level detected that the riser was not installed straight, you have to cut from the horizontal pipe. To see the latter, you need to dig further (if you haven’t yet).

Installing a waste pipe on a concrete floor also means that it needs to be straight or level, or else it will result in a wobbly toilet.

Step 6: Assemble the Pipes


  • Before we glue anything, we need to perform dry fitting first. This is when you position the pipes to test fit them and give a clear image of where you want the pipes to go.

You will do a lot of adjusting and twisting to get the perfect fit.

  • After the dry fitting, use the spirit level to make sure that the riser pipe is level.
  • You also want to measure the clearances and rough-in to ensure that the new fittings will achieve them.
  • Mark the dry-fitted pipes, so you would know where and how far you have to glue them together.
  • Once ready, remove the dry fitting. Put the primer on the area where the pipes will be stuck together before putting the actual glue. The latter will vary depending on the type of pipe.

In the photo example below, PVC glue was used; the violet fluid is the primer.

  • Follow the markings carefully while assembling them.
  • The last task in this step is installing plumbing in the existing concrete slab. Carefully connect the assembled pipe following the mark.

Use sandpaper to polish the old pipe, where we will connect the new ones for a better grip. Also, ensure that the riser pipe is level with the floor.

Step 7: Finalize the Work


We’ve already extended the drain. What’s left is to finalize our newly moved waste pipe to install the toilet back.

  1. First, cover the pipe’s opening with plastic secured by a rubber band to prevent dirt and gravel from entering.
  2. Fill the hole alternating with dirt and gravel, making sure each layer is level. 
  3. Place a polyethylene vapor barrier on top of the last layer before pouring the already-mixed concrete. 
  4. Once you pour in the concrete, level it to the floor and let it dry. You can put the toilet flange in once the drain is ready. 

Frequently Asked Questions (FAQS)

How Far Can You Move a Toilet Drain?

In moving a toilet drain, we have to consider the diameter of the waste pipes. The wider the diameter, the more successful the flow rate of the waste. 

  1. If your waste pipe has 3 diameters, you can relocate the toilet 6 feet away.
  2. If your waste pipe has 4 diameters, you can relocate the toilet 10 feet away.

How Hard Is It to Move Toilet Plumbing?

The difficulty of moving a toilet’s plumbing will depend on the following: 

  1. how far you want to relocate it;
  2. other challenges that may arise in the process, such as having a steel bar in the way (floor support) and;
  3. your skill level.

With this being said, it’s better to contact a professional plumber if you’re planning to move a toilet drain on the second floor, as this can be more complicated than just moving it a few feet.

How Do You Move a Toilet by Yourself?

Moving a toilet by yourself involves measuring, breaking the concrete floor, cutting the riser pipe, installing new pipes, and restoring the concrete floor. It’s manageable to be a DIY job but if you’re unsure of what to do, hire a plumber instead.


Moving objects around that aren’t attached to your house is easy, but how about plumbing fixtures? The answer to how to move a toilet drain in concrete is to always measure the toilet clearance first. 

Next, we have to break the floor with a jackhammer and cut the riser pipe to give room for the new pipes; ensuring that everything is level is crucial. After this, we have to layer dirt and gravel to fill the hole before pouring concrete to secure the entire work and restore the floor. 

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