Standard Toilet Rough-In Size: How Do You Measure Toilet Rough-In With Simple Steps?

When it comes to important rooms and spaces in a home, everyone thinks about the bedrooms and the kitchen, while the bathroom often goes overlooked. The toilet space is one of the unspoken but essential areas in a home.

For a bathroom to be functional as well as hold the proper aesthetics, the positioning of the toilet is very important. And for it to be placed in the best spot, you need to make sure the toilet rough-in size is suitable from all sides.

Keep reading because I have gathered all the information you need to know about your toilet’s rough-in size and how you can measure it properly.

What Does Toilet Rough-In Mean?

To put it simply, rough-in is the length between the wall and the center pipe of the toilet. This might not seem too significant considering the overall bathroom space, but your toilet placement depends on it.

First of all, you should keep in mind that toilets come in different sizes, so their rough size will also vary accordingly. So if there is not enough or too much space between the back wall and the drainpipe of your toilet, then you will have to make other adjustments.

Those other adjustments include making the wall thicker or thinner or changing a lot of the pipes and plumbing in the toilet. Overall, making such changes will cost you a lot of money.

So before you go out and buy a toilet for your bathroom upgrade project, you first need to measure the rough-in. Prior to doing that, there are a few other things you need to take into consideration.

What Are The Traditional Rough-in Sizes for Toilets?

The universally standard toilet rough in size is 12 inches. But do note that 10″and 14″are also considered standard in some countries.

For a 10″toilet, you can easily fit it in a bathroom that has enough space to allow a 12″or 14″one. Although there won’t be any issues with the fitting and placement, the inconsistency in space allocation will make the toilet appear misaligned in the bathroom.

Some toilets come in two separate parts, which are the tank and bowl. Such a toilet can also be arranged to fit in a larger space. However, it still won’t be perfect, and I would suggest you not do this.

As you can already guess, you won’t be able to fit a larger-sized toilet in a space with minimal clearance in any way. Hence, it is extremely important to take the toilet rough-in measurements before doing anything. We will now look at how you can do that in different ways.

Measuring Rough-in When There’s No Toilet Installed

Taking the rough-in measurement is the easiest if you’re just building a new home and haven’t purchased any of the big items. Now is the time to call in your plumber and make the necessary measurements for your toilet fitting. Here is what you need to do:

Locate The Toilet Flange Or Drainpipe

The drainpipe is a hole in the ground where all the waste will drain. It is usually placed close to the back wall of where the toilet is intended to fit. There might be a plastic lining on the hole, which is the toilet flange.

Measure from Center of Drainpipe to Wall

Take out your case tape measure and hold it perpendicular against the wall, and measure till you reach the midpoint of the drainage pipe. Don’t forget to consider the wall studs or any other moldings while measuring.

However, if your house is still being built and the wall lines haven’t been drawn and fixed yet, you have to take the rough-in measurement later.

After taking the measurement, if you find that it is a value other than 10″, 12″, or 14″, then you haven’t done it correctly. Repeat the process to get an accurate reading.

If you confused about the 10 inch Vs 12 inch Vs 14 inch Rough-In Toilet, Check the detailed comparison HERE.

Measuring Rough-in When There’s A Toilet Installed

This is a bit tricky, but not impossible. You just have to be careful regarding your measurements and how you take them. What you have to do is measure from the wall to the bolts holding the toilet in place, as those line up with the center of the drainpipe.

Here is how you will do it:

Locate The Bolts Holding The Toilet in Its Position

Check the base of your toilet and see where the bolts or caps are. These are typically on the left and right sides of the back area of the base.

Your toilet might have a skirted design, so for that, you have to find any indentation or notches that indicate where it is bolted. It is best to mark those spots with painter’s tape for your convenience while measuring.

Read Measurement from Wall to Bolt

Now with your measuring tape, take the measurement from the wall and up to the bolts or where you have marked the base of the toilet. For wall studs or molds, start the tape from the bare wall instead of where the new texture starts.

Once again, any length that is not 10″, 12″, or 14″means you have measured it incorrectly. So just repeat and take your measurement carefully.

What’s The Process for Finding Rough-in Size for Corner Toilet

This is another situation where measuring the rough-in size can be a bit complicated. But there is no need to worry, as you just need to follow a couple of extra steps.Here’s how:

Identify The Drainpipe’s Center

Your job will be easy if there is no toilet placed yet, as you can already just see where the toilet flange is. To find the center of the drainpipe that is already installed, just look for the bolts on either side of the toilet.

Think about two lines that cross the bolts on either side. The crossing point of the lines is where the center of the drainpipe is located. You can use painter’s tape to mark this spot for easy reference.

Check The Distance from The Walls on Each Side

Now that you know where the center of the toilet flange is, measure the distance from that to the adjacent walls at a 90-degree angle. The point where the lines from both the walls meet is the size of your toilet’s rough-in.

What’s The Process for Finding Rough-in Size for Wall Mount Toilet

Unlike traditional toilets, where the drainage happens through the floor, the waste goes through the wall for wall-mounted toilets, hence the name.

So instead of measuring horizontally from the floor, you have to take your measurements vertically from the wall to find the rough-in size.

An advantage you get with wall-mounted toilets is that you don’t have to worry about little or too much space for fitting the toilet against the drainpipe. However, you should still take the measurement carefully to ensure a perfect fit. Here is how you will do it:

Find The Center of The Drainpipe

You can easily find this if the toilet hasn’t been set yet. All you need to do is measure upwards from the floor and up to where you see the middle of the drainpipe in the adjacent wall.

But if the toilet is already installed, measuring the rough-in can be a bit difficult, so you will just have to go with your best estimation. There is no need to worry, as the rough-in size for wall-mounted toilets doesn’t need to be super accurate, as managing the plumbing is easier in this case.

Some Building Codes to Consider for Toilet Rough-in

Although the rough-in measurement is very important for installing a toilet, there are other measurements you should still consider which will affect the overall installation.

For example, the amount of space left in front of the toilet and at the sides is very important. After all, we need to sit comfortably in the toilet and have enough leg space. Different regions follow certain building codes when planning for bathroom and sanitation items.

Standards such as the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC) state that there should be a minimum of 21″and 24″in front of the toilet, respectively. So be sure to check with your local interior designers regarding any specific building codes before installing your toilet.

One thing to keep in mind is that all your measurements will be based on what you read from the center of the drainpipe. So if you’ve got that down correctly, you don’t have to worry about the rest of the measurements.

Height of The Toilet

When considering comfort, you should also consider the toilet’s height, which is measured from the base to the rim. This does not depend on any building codes or rough-in sizes but is necessary to keep note of to ensure comfort while sitting on the toilet.

Frequent Mistakes Made While Measuring Rough-in

Even if the steps for measuring the rough-in seem straightforward, there are some common errors we tend to make:

Disregarding The Baseboard

Many people make the mistake of measuring from the drainpipe center to the bottom of the floor. In contrast, they should take the measurement a bit higher so that it is above the baseboard.

This difference might be negligible, but it can mess up the plumbing measurements a great deal.

Not Considering Wall Studs

If you have studded walls, about half to one inch is automatically added to your measurement. It is important to measure from the bare wall or subtract the studs’ thickness from your measurement.

Missing The Center of The Drainpipe

Measuring from the front or back of the drainpipe instead of the center will give you an inaccurate size for the rough-in. So you must be very careful and ensure that you measure from the exact center of the toilet flange.

Frequently Asked Questions

Q. How do I know if my toilet is a 10 or 12 rough?

Measure from the center of your toilet’s bolts to the surface of the drywall. If you get anything around 11-12 inches, that means your toilet is 12 rough. Below that means it is a 10.

Q. Are all toilets 12 rough-in?

No. Although 12″is the standard size, there are also 10″ and 14″ rough-ins for toilets, which are common.

Q. How far is rough-in a toilet from the wall?

Considering drywall to be about ½ inch in thickness, your plumber should rough-in the toilet flange about 15.5 inches from the wall to the center of the drainpipe.

Q. Does toilet rough-in need to be exact?

If you plan on a toilet arrangement other than a wall-mounted one, then yes, the rough-in size needs to be exact for proper plumbing, drainage, and comfort.

Q. What size hole do I drill for the toilet flange?

Depending on the thickness of the waste pipe, the toilet flange hole should be 3 or 4 inches in diameter.

Q. Should there be a gap between the toilet and the wall?

Usually, builders keep a 1-inch gap between the toilet and the back wall. Most importantly, there should always be a 15-inch clearance from the center of the toilet to the back or side wall for proper plumbing.

Q. How far should a toilet flange be above the floor?

The best height for a toilet flange to be placed on the floor is about ¼ of an inch.

Q. Should you caulk around a toilet?

This depends on the building code of the area in which you live. If your region’s building code enforces builders to caulk around a toilet, then it is required.

Final Words

Installing a toilet is no easy task and is definitely not a cheap feat. The main problem you will face when getting the wrong rough-in size is that you will have to make adjustments later on, either with the back wall or internal plumbing.

All of that involves tearing and breaking down some polished interior work and will cost you a lot of money. So it is important that you get the correct toilet rough-in size measurement the first time, so no changes need to be made afterward.

Hello, I'm Jon C. Brown, an expert in the field of toilets. With over 15 years of experience in this industry, a significant portion of my life has been devoted to crafting high-quality toilets and bathrooms. Consequently, I've received countless inquiries about the toilet and bathroom industries. That's why, I've launched this website to provide top-notch solutions for all your toilet and bathroom related needs.

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