Skip to Content

Toilet Rough In: All You Need to Know

Whether you’re building a new toilet or remodeling your old one, knowing the measurements is important. Especially the measurements of your water and waste disposal lines. So, having an idea about the rough ins is important. 

What is a toilet rough in?

The toilet rough in refers to the location of the waste disposal outlet in your toilet. The rough in can either be on the floor, or on the walls. A typical rough in is the distance from the center of the toilet to the wall behind it.

Knowing the measurement of your rough in is a key factor in designing any toilet. But that’s not all. In this article, we’re going to discuss rough in’s and its technicalities. 

Let’s begin! 

What Is A Toilet Rough In?

In layman’s terms, the rough in is a measurement of where the toilet will sit. While this might look simple, there are some technicalities involved. 

When it comes to rough ins, you have to keep two factors in mind. These include the area where the waste outlet hole is placed. And the distance between the wall and the outlet.

This is most important during the renovation of your toilet. Quite often people buy toilets based on the size of their old ones. However, due to different rough ins, they don’t quite set. The rough in is what defines the fit, not the toilet itself. 

Miscalculating and placing the wrong toilet can cause a fair bit of trouble. These include toilet seats not being in place and toilet not filling up. So, measuring the rough in is important. 

Types of Rough in

Now that we’ve discussed what a rough in is, we need to discuss the types. Generally, three types of rough ins are seen in toilets. These include-

10-inch Rough In

They aren’t that popular, 10-inch toilet rough ins are seen mostly in older homes. Here, the distance between the disposal line and the back wall is 10 inches. 

 The short size doesn’t provide a lot of room. As a result, most toilet bowls you’d see in a 10-inch rough in are round. Also, since the size is small, dust management is harder. As a result, you may end up with brown stains at the bottom of the bowl.

12-inch Rough In

The most common type of rough in is the 12-inch one. Most modern houses feature a 12-inch rough in for versatility and ease of use. As a result, you’d see toilet bowls in different sizes and shapes.

Since it’s the most common, people assume their toilets to have a 12-inch rough in. However, we recommend measuring thoroughly before getting one. 

14-inch Rough In 

Similar to 10-inch rough ins, the 14-inch ones aren’t much available either. They’re mostly seen in small bathrooms in older houses. However, you can expect a bit more variety in this case. There are multiple sizes and designs for 14-inch rough ins.

How to Measure A Toilet Rough In?

Measuring the size of your toilet can be a bit technical. However, it’s important to get it done fast. Here are the steps to measure a toilet rough in-

Step 1: Distance from The Toilet Flange to the Back Wall

Your rough in length is based on the distance between your toilet flange and the back wall. So, this is the first thing that you should measure.

Take a measuring tape and start measuring from the center of the flange. Measure up to the finished wall and take notes. If you have a stud wall, add its thickness to the total.

Most toilet walls have a ½” drywall behind them. If you have drywall, add its thickness to it as well. For example, if you have a 12” rough in, the final measurement will be 12.5”

If you’re looking for the right flange for your toilet, check our recommendations-

Product 1
Product 2

These are some of the best flangs out there! Check them out for more!

Step 2: Distance from The Center of The Toilet to Adjacent Fixtures 

You need to provide some space for your toilet. So, you need to keep at least 15” clear on its sides. So, from the center of the flange, measure to the closest fixtures on its left and right. 

In case you don’t have anything on the side, measure the distance of the nearby walls. Similarly, take the measurements of drywalls, mosaic, or stud walls into account. 

If you have any renovations planned for the future, take that into account as well. Otherwise, something as simple as the wrong shower arm angle could take up too much space. Making the toilet unusable,

Step 3: Distance From The Front to Any Obstructions 

If your toilet doesn’t have some distance from the front, it will be uncomfortable to use. Now, the distance between obstructions is generally determined based on the local plumbing code. 

In case your locality is under the IPC, you need at least a 21” distance. If it’s under the UPC, it will require up to 24” distance. So, check your local plumbing codes beforehand. Because you don’t want to violate any of the plumbing codes in your area. 

If the obstructions are too close, using the toilet will be a hassle. So, keep that in mind.

With that, we’ve discussed all that you need to know about rough-ins! 


Question: Can you get a 12-inch toilet bowl for a 10-inch toilet? 

Answer: No! Your toilet bowl should match the size of your rough in. Otherwise, it won’t fit! So, make sure to measure carefully before getting one!

Question: Can you put a toilet on the inside wall?
Answer: You can place your toilet on an internal wall as long as you have space. If there’s room underneath for the water line to run, you can place your toilet. 

Question: How far should the toilet be from the soil pipe? 

Answer: The maximum distance depends on the diameter of the waste line. If the line is 3-inches, it can’t be more than 6-feet away. If it’s diameter is 4-inches, the maximum distance should be 10-feet.

Final Word 

Maintaining your toilet is a mammoth task. Any problems there can be annoying as well as costly. However, keeping everything in check is important. Having an idea about the toilet rough in is important in that regard. 

In this article, we’ve discussed all the technicalities of rough ins! We’ve discussed topics from their characteristics to measuring one properly! We hope you find this article helpful!