Toilet pit distance (also rough-in or pit spacing) explained in the images:
What is a toilet pit distance (also rough-in or pit spacing)?
Toilet pit distance (rough-in, pit spacing) is the distance between the center of the toilet drain outlet and:
a.) the backside of the toilet (ground/floor drainage toilet with S-trap – toilet with bottom discharge);
b.) the bottom of the toilet (back/wall drainage toilet with P-trap – toilet with rear discharge).
There are three sizes of pit distances for the ground/floor drainage (bottom discharge) toilet: 10 inch / 250mm, 12 inch / 300mm or 16 inch / 400mm. So, this is the distance between the backside of the toilet and the toilet drain outlet. The standard (and the most commonly used) pit distance is 12 inch (300mm) for the ground drainage toilet.
For the back/wall drainage (rear discharge) toilet (drainage to the wall, not to the ground), the standard pit distance is 7 inch / 180mm. This is the distance between the bottom of the toilet and the toilet drain outlet.
Most of the ground drainage toilets we sell have pit distances of 12 inch / 300mm or 16 inch / 400mm, and some selected toilets have a pit distance of 10 inch / 250mm. Back/wall drainage toilets have a pit distance of 7 inch / 180mm.
Ground/floor drainage toilet, S-trap
For example, if the bathroom ground drainage pit distance is 280mm / 11 inches (distance from the tiled wall to the center of the sewer pipe on the ground), 10 inch / 250mm pit distance toilet can be installed, however 12 inch / 300mm and 16 inch / 400mm pit distance toilets cannot be installed. If the bathroom ground drainage pit distance is 430 mm (17 inches), all toilets with the ground drainage can be installed, but the best is 16 inch / 400mm pit distance toilet as it goes closer to the wall.
Back/wall drainage toilet, P-trap
If the bathroom has a wall drainage (not the ground drainage), the toilet with back drainage (7 inch / 180mm pit distance) should be chosen.
NB!! If you are unsure what toilet pit distance you need, send us a simple drawing / photo of your bathroom with the dimensions and we can help to confirm it for You.