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What Is A Toilet Rough In

Aug 11, 2017

Toilet rough in is the distance between the drainage hole and the back of the toilet ,but how to obtain the accurately dimension, renovators should start at the back of the toilet and measure the distance to the center of the waste outlet hole on the underside of the bowl. Usually, this measurement is 12 inches (30.5 cm), but manufacturers also offer toilets to accommodate 10 inch (25.4 cm) and 14 inch (35.6 cm) toilet rough in measurements that may be needed due to construction mistakes or awkward floor joist placement.

For example: this toilet is washdown toilet, and the size of rough in is 305mm.


Purchased toilets must be correspond to the rough in measurement, otherwise the toilet won’t match the drainage pipe location. Sometimes, renovations will require the toilet rough in be moved, which means the drainage hole must be relocated to another area of the bathroom. If no toilet currently exists in the space, the rough in can be identified by looking for a drainage hole with an external “lip.” This lip is called the flange, and it will have a wax ring surrounding it.

Installing a toilet over an existing rough in is very simple, but relocating one can be tricky and should only be handled by someone with prior plumbing knowledge, but the floor must opened up, and if the bathroom is at basement level, this will entail breaking through the concrete. Also, considerations must be made regarding the water line, drainage line, and pipes. Redirecting these could result in plumbing flow problems, plus there are specific plumbing codes that must be followed.

Simply replacing the toilet does not warrant any kind of notification, but any time pipes are altered, permits may be required. It’s essential to follow the plumbing and building code exactly, because a permit may also lead to a required inspection and approval. This is necessary because any time pipes are altered, it could affect the balance between drain and vent segments.

So please kindly tell us your size of the rough in ,or let us know your toilet situation ,we might give you a professional advice.