In plumbing codes, what is often the minimum trap diameter for toilets?

The minimum trap diameter for toilets is typically specified as 38 mm in plumbing codes. This dimension ensures that the trap is sufficiently sized to handle the waste and water flow from the toilet while preventing blockages. A trap of this size can maintain proper siphoning action and facilitate the effective removal of waste. It is designed to retain a water seal, preventing sewer gases from entering the building while accommodating the expected volume of waste.

While other sizes are listed, they do not align with the established standards for toilet traps, which prioritize both function and compliance with plumbing regulations. A trap that is too small may lead to clogs and insufficient drainage, while larger traps are not required for toilet installations.