Can You Replace a 14 Inch Rough In Toilet With a 12 Inch Rough In Toilet?

Rough-in is the measure of the distance from the drain hole to the wall behind the toilet. It is essential to measure the accurate rough-in when renovating the bathroom interior or selecting a new toilet for this place.

Can You Replace a 14 Inch Rough In Toilet With a 12 Inch Rough In Toilet? You can replace a 14 inch rough-in toilet with a 12-inch rough-in toilet, which leaves an extra distance of 2 inches from the wall. You can fill the space by installing a shelf or cabinet or using an offset flange to reduce the distance from the wall. The 12-inch rough in toilets are more universal than the 14 inch rough in and are considered standard in America.

Professional recommends selecting the same size toilet if you want to replace the toilet because the smaller size can leave some extra distance of the toilet tank from the wall.

Why would you replace a 14 inch rough-in toilet with a 12 inch rough-in toilet? 

You may need to replace the old toilet with a new one that is more environment-friendly or accommodate the space available in this place.

The 14-inch rough-in toilet takes more space, and I want to change it with a small one when remolding the bathroom interior.

The old plumbing fixture may get damaged, or the flushing system may slow down over time, and you want to change it with another toilet.

Moreover, 12-inch rough-in toilets are the standard in America because they are universal, and everyone can use them conveniently.

The modern plumbing system considers the 12-inch as the most preferable and standard rough-in nowadays.

Therefore, you can install a toilet on the existing rough-in easily, but it causes the entire plumbing system to alter if you relocate it to another place. 

How can you replace a 14 inch rough-in toilet with a 12 inch rough-in toilet?

Firstly, measure the toilet rough in without the existing toilet over the drain hole. The drain hole is around the flange opening and cut into the floor as a round hole.

Use a measuring tape and place it from the drain hole to the bare wall, and if you have installed tiles or baseboards on the wall, then a half-inch extra error can occur in the measurements.

For example, if you measure 14.5 inches for the existing toilet with the tile wall, which means the correct measurement is 14 inches. Measuring the distance from the bare wall is better to avoid any measurement error.

Now, place the new 12-inch rough-in toilet over the flange and screw the nuts and bolts to secure the connections.

Replace the traditional flange with an offset one that allows 1-2 inches extra distance towards the wall because installing a 12-inch over a 14-inch rough-in causes an extra 2-inch space.

Replace the old flange by removing the nuts and screws and installing an offset flange over the drain hole. Then, install the 12-inch rough-in toilet over the flange and connect all the connections. Turn on the water and access its performance.

You can replace it without replacing the old flange and cover the 2-inch extra space by installing a shelf over the toilet.

You can use this shelf to place toilet cleaners or the paper holder, as replacing the flange can be exhausting if you do not have experience doing such projects yourself.

Difference between 12-inch and 14-inch rough-in toilets

Since 12-inch rough-in toilets are more common and preferable to install in the bathroom, you can replace them if you have a damaged 14-inch toilet.

The 12-inch rough-in has a distance of 12 inches from the center of the drain hole to the bare wall, while a 14-inch rough-in has a 14-inch distance between the drain hole and the wall.

The 12-inch rough-in fixture can accommodate small bathroom space, while the 14-inch plumbing fixture needs more space because of its larger size.

In addition, it requires more space between the wall and the toilet and is complicated to install, especially in congested areas.

Another difference between these two is the cost, such as the 12-inch toilet being less expensive than a 14-inch because it has a unique feature and limited variety. Therefore, the manufacturing cost causes an increase in its price and demand for large bathroom areas.

The 14-inch rough-in has excellent flushing ability and can clean the bowl thoroughly with one flush and prevent clogging inside the drain pipes.

The smart design can save approximately 1700 gallons of water and has a comfortable design and height to sit on the seat. However, the 12-inch rough toilets are installed more frequently than the 14-inch rough in because of their standard size.

What are the disadvantages of replacing a 14 inch rough-in toilet with 12 inches rough-in toilet?

It is better to select the same rough in when changing the toilet in the bathroom because replacing a 14-inch with a 12-inch can cause the following disadvantages.

Extra space from the wall

Since they are larger than the 12-inch rough-in, they can leave extra space between the toilet and the wall.

The space looks unappealing, and moisture can accumulate on the wall behind the tank. I have replaced a 14-inch rough-in plumbing fixture with a 12-inch, and it causes a 2-inch space between the wall and the toilet, which looks unattractive to the overall bathroom interior.

You can use this extra space to avoid mold and moisture in this place by installing a cabinet or shelf to fill the gap with other filling material.


The incorrect measurement can cause the wobbling of the toilet when someone sits on the toilet seat because the plumbing fixture cannot fit well into the drain hole.

Another reason for a rocking toilet can be improper installation, especially if replacing the flange with an offset flange, because the process can be more time-consuming and tricky.

The tank can also wobble because of the distance from the wall, and you do not feel comfortable if the fixing and the installation are not correctly done.

Damage to the wax or sealing

The wobbling of the tank and the toilet can cause the wax ring to be damaged if someone leans back on the seat.

The incorrect measurement of the rough-in can cause the inaccurate fixing of the toilet on the drain hole, and the sealing can deteriorate over time when more people use it.

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