If you are remodeling your bathroom, you may be considering moving your toilet. Moving your toilet can be a lot of hard work and requires a lot of knowledge. One thing you must know when moving your toilet is how far it must be away from the stack. 

In short, your toilet must be no more than 6-feet away from the stack if the waste line diameter is 3-inches. If the waste line diameter is 4-inches, the toilet must be no more than 10-feet away from the stack. Read on to find out more about the distance between the toilet and stack and moving your toilet. 

Distance Between the Toilet and Main Stack 

The distance between the toilet and main stack depends on the diameter of the waste line. If the waste line has a 3-inch diameter, the toilet should be no more than 6-feet away from the stack. In contrast, the toilet should be no more than 10-feet away from the stack if the waste line is 4-inch in diameter. 

The reason that the diameter of the waste line affects the distance between the toilet and stack is that it changes the slope of the pipe. You always want the drop rate of the pipes to be ¼-inch per horizontal foot. The larger the diameter, the further away the toilet can be from the stack in order to maintain the correct slope. 

Why Would You Measure the Distance Between the Toilet and Stack?  

You would want to measure the distance between the toilet and stack if you are moving your toilet. If your toilet is not being moved or changed in any way, you should not need to measure the distance between the toilet and stack. 

Aspects of Moving a Toilet 

When you move a toilet, you will need to move the drainage, water supply plumbing, and fixture. The fixture is the easiest part to move, while the drainage and water supply plumbing are difficult to move.

Moving the Toilet Drain 

There is a series of drainage pipes under the bathroom floor. These pipes are normally 3- to 4-inches in diameter and have an intricate route that darts between other pipes and flooring joists. Drainage pipes are controlled by gravity, which means they must have a specific drop rate for the waste to drain properly. 

The drainage pipes should drop at a vertical rate of ¼-inch per horizontal foot. This fact means that the toilet must be an appropriate distance away from the stack to keep this slope rate. If the waste line diameter is 3-inches, the toilet should be a maximum of 6-feet away from the stack. If the waste line diameter is 4-inches, the toilet should be a maximum of 10-feet away from the stack.  

Moving the Water Supply 

Once the toilet drain is moved, you can move the water supply. This aspect is less difficult and does not involve the distance between the toilet and main stack. Water supply pipes are much smaller and can be moved around easier. You may want to connect the relocated supply line to the existing toilet line. 

How to Move a Toilet  

Moving a toilet can be extremely difficult. This project is only recommended for those experienced with toilet renovations and toilet plumbing. If you are not comfortable with renovating the toilet yourself, you should hire a professional to do the job for you. With this in mind, here are the 10-steps to moving your toilet. 

  1. Remove the Toilet 

Remove the toilet. If you are reusing the toilet, be gentle with the fixture to prevent it from breaking or chipping. If you do not plan to reuse the toilet, dispose of it in a responsible manner. Then, force a rag in the drainpipe so you don’t lose tools down the pipe and block gases from rising. 

1. Gain Access 

Access the toilet drainage lines that run through the flooring system of the bathroom. You can access the drainage lines from above or below. To access from above, use a saw blade to cut out about 1/8-inch into the subfloor. To access from below, demolish the drywall ceiling from below. 

2. Remove the Flange 

Using a screwdriver or drill driver, unscrew the toilet flange and remove it from the drainpipe. You may need to use a hammer or reciprocating saw if the toilet flange is sealed down. 

3. Cut the Toilet Bend

Use a reciprocating saw to cut away the previous toilet bend. Make it as close to the waste vent stack as possible. 

4. Position New Drain Location

Position the new drain. It should be at least 15-inches from the center of the drain to any sidewalls, which includes the shower or bath. 

5. Run New Drain 

Run the new drain from the new toilet location to the waste vent stack. Make sure that the toilet is positioned correctly to the stack. If the pipe is 3-inches in diameter, the toilet should be no more than 6-feet away from the stack.

Similarly, if the waste line is 4-inches in diameter, the toilet should be no more than 10-feet away from the stack. 

At the stack, install a new wye fitting where you severed the old drain. Use a 90-degree bend to direct the pipe to the toilet. Fit the pieces together with an appropriate glue. As you glue, ensure that the lines slope at ¼-inch per horizontal foot toward the stack. 

6. Install the Drain Stub-Out 

Install the drain stub-out. Glue a 90-degree toilet bend to the end of the new drain. Also, attach a 6-inch pipe into the upward facing socket so that it goes through the floor. 

7. Run the Water Supply Lines 

Continue the water supply using a PEX pipe through the joists. There’s a number of ways that you can connect the tubing to the existing copper pipes. Research which technique works best for you. Place a copper stub-out elbow with a flange and stud nails where the pipe emerges through the wall. 

8. Fit the Flange

Replace the subfloor and cut off the drainpipe flush so that it is level to the finished floor. Install toilet closet flange on top of the flooring. 

9. Install the Toilet 

Finally, install the toilet on top of the toilet closet flange. Connect the fixture to the water supply and turn it on. 

Related Questions

Should I move my toilet? 

Moving a toilet can be a lot of hard work and money. A lot of sensitive factors are involved. So, it is not a task for just anyone. You should relocate your toilet if you are already working on bathroom plumbing, the toilet position is currently disadvantageous, or if you or someone you know is confident with toilet plumbing. 

You should not move your toilet if you do not have the funds, resources, or time to properly adjust the toilet drainage, toilet vent, and water supply. 

What do I do if my bathroom floor is concrete? 

If the former bathroom floor is made from concrete, you will have to demolish the concrete to access and relocate the water and waste lines. Once they’ve been accessed, you will need to rebuild the concrete foundation and replace the subflooring, flooring, and fixtures. This will make moving your toilet more time consuming and costly.