Trade Terms

P-Trap

A curved section of pipe under a sink or fixture that holds water to block sewer gas from entering the building.

The P-trap (named for its shape) is a fundamental plumbing fitting. The water trapped in the curve forms a seal preventing sewer gas from entering the building through the drain. Required by code on every plumbing fixture. A dried-out P-trap (from a rarely-used drain) is one of the most common causes of sewer-gas smells in a building.