Chances are if you are asking yourself this question you may have been told by your builder or designer that the toilet needs to be placed against the outside wall. While there are good reasons to do so, it is not always necessary. In fact, many bathroom layouts have the toilet set against an internal wall.
Can a Toilet go on internal Wall?
There is no hard-fast rule about whether a toilet should touch the wall, as it is a matter of personal preference. Some people are okay with a toilet tank’s top touching the back wall, while others desire a minimum of one inch of space between the commode and the back wall
When toilet flanges are installed it is typically in the early stages of the project and the standard 12″ measurement is taken from the drywall, rather than the finished tile surface that you are measuring from. That means your flange was set at a distance further from the wall than even the 13″ you measured.
On a serious note, it is absolutely possible to install a toilet, even a bathroom as a matter of fact, anywhere in your house. In the past, many homeowners have had the idea of their dream bathroom crushed because the location was simply too far away from the main drain.