S-Trap or P-Trap? How to Identify Your Toilet Drainage Before Upgrading to a Smart Bidet

Before upgrading to a smart toilet, first identify whether your bathroom uses an S-trap floor outlet or a P-trap wall outlet. Choosing the wrong drainage type can prevent the toilet from aligning with the existing waste pipe.

S-Trap: Floor-Outlet Drainage

An S-trap toilet discharges vertically into the floor. The key measurement is the rough-in distance from the finished wall to the center of the floor drain.

BBBIDET offers selected S-trap models in several rough-in configurations, including common 250mm, 300/305mm, 350mm and 400mm options depending on the model.

P-Trap: Wall-Outlet Drainage

A P-trap toilet discharges horizontally through the wall. For this layout, measure the height from the finished floor to the center of the wall waste outlet and compare it with the exact product specification.

Browse BBBIDET P-Trap Smart Toilets for floor-mounted wall-outlet options. The K80, for example, is available with a 180mm P-trap configuration as well as multiple S-trap versions.

How to Measure the Rough-In

For an S-trap, measure from the finished wall to the center of the floor drain. For a P-trap, measure from the finished floor to the center of the wall outlet. See the full Smart Toilet Rough-In Guide for measurement examples.

Which Drainage Type Should You Choose?

Choose the toilet configuration that matches the existing plumbing unless your renovation plan includes moving the waste outlet. Do not select a model only by appearance or functions. Drainage type, rough-in, water connection, electrical supply and available bathroom space should all be confirmed before ordering.

For small bathrooms, compare Compact Smart Toilets. For low or variable water pressure, see Smart Toilets for Low Water Pressure and Smart Toilets with Built-In Tanks.

B2B Smart Toilet Selection

Distributors, retailers and project buyers can use Smart Toilet Supplier to compare the wider product platform. For manufacturing and OEM/ODM requirements, visit Smart Toilet Manufacturer.