The Complete Guide to Toilet Rough-In Dimensions

The distance from the toilet flange, or "pit distance," must be measured carefully before installation; otherwise, you may encounter issues with installation after purchase. Below, I'll introduce the different types of pit distances for toilets.

Types of Toilet Pit Distances

Toilet pit distances typically measure 300mm, 400mm, and 450mm, with 300mm being the most commonly used distance in homes. The pit distance refers to the distance from the wall to the center of the flange. When installing the toilet, it’s essential to leave approximately 20mm for the wall tile, so the center line of the waste outlet should be around 320mm or 420mm from the wall. A difference of 10mm is considered normal.

How to Choose a Home Toilet

1、Toilet Glaze

When selecting a toilet, first check the glaze on the surface. Generally, a toilet with a smooth and even glaze is preferable, as it tends to have better self-cleaning capabilities and is less likely to develop yellowing over the years. When choosing a toilet, you can touch the waste outlet; if it has an entire glazed finish, it will resist staining and be easier to clean.

2、Hardware Accessories of the Toilet

Pay attention to the toilet’s hardware components as well. Most parts are located in the water tank, making it difficult to assess their quality from the outside. You can test the flushing mechanism on-site; if the button feels loose, it indicates poor elasticity, making it prone to damage. Conversely, if the button feels sturdy and responsive, it indicates good elasticity.

3、Difference Between One-Piece and Two-Piece Toilets

Also, consider the structure of the toilet, which can be either one-piece or two-piece. Aside from the water tank, their functions are the same. Two-piece toilets are usually simpler to manufacture and thus tend to be more affordable, while one-piece toilets have a lower production yield and are generally more expensive. Choose according to your actual situation.

4、Choosing Between Siphonic and Flush Toilets

Consider the flushing mechanism as well. Toilets can be siphonic or flush type, each having its advantages and disadvantages. For instance, siphonic toilets are quieter during flushing, maintain higher water levels, and don’t emit unpleasant odors from the drainage pipe, but they tend to use more water. On the other hand, flush toilets are louder but more water-efficient.

In summary：this covers the various types of toilet pit distances. Toilet pit distances typically measure 300mm, 400mm, and 450mm, with 300mm being the most common in homes.