What is a toilet pit distance / pit spacing?

What is a pit distance (pit spacing)?

Toilet pit distance (pit spacing) is the distance between the toilet drain outlet and:

  1. the backside of the toilet (ground drainage toilet with S-trap);
  2. the bottom of the toilet (back drainage toilet with P-trap).

There are three sizes of toilet pit distances for the ground drainage: 250mm, 300mm or 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 300mm for the ground drainage.

For the back drainage toilet (drainage to the wall, not to the ground), the pit distance is 180mm. This is the distance between the bottom of the toilet and the toilet drain outlet.

Most of the toilets we sell have pit distances 300mm or 400mm (ground drainage), and some selected toilets have a pit distance of 250mm (ground drainage) and 180mm (back / wall drainage).

Ground drainage toilet, S-trap

If the bathroom ground drainage pit distance is 260mm (distance from the tiled wall to the center of the sewer pipe on the ground), 250 mm pit distance toilet can be installed, however 300 mm and 400 mm pit distance toilets cannot be installed. If the bathroom ground drainage pit distance is 420 mm, all toilets with the ground drainage can be installed, but the best is 400 mm pit distance toilet as it goes closer to the wall.

Wall drainage toilet, P-trap

If the bathroom has a wall drainage (not the ground drainage), toilet with back drainage (180mm pit distance) should be chosen.


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.

Pit distances explained in the images: