What is the diameter of a lavatory tailpiece?

The traditional lavatory tailpiece has a diameter of 1-1/4 inches while modern sinks have tailpieces with diameters of 1-1/2 inches. The lavatory tailpiece securely connects your sink to the waste management system in your building.

The top of the tailpiece is connected to the sink drain while the bottom is connected to the P-trap. A lavatory tailpiece can be made of PVC or metal. A plumber is not required to fix or replace the lavatory tailpiece, but those unfamiliar with plumbing may want to considering hiring a professional.