Wyes

What Is a PVC Wye Used for in Plumbing?

A PVC wye (Y-fitting) is a drain fitting used in drain, waste, and vent (DWV) systems to connect a branch pipe into a main pipe at a smooth 45-degree angle instead of a sharp 90-degree turn.

Its main purpose is to:

• Direct wastewater smoothly into another pipe
• Reduce clogs and turbulence
• Maintain proper drainage flow

What a PVC Wye Does

• Allows one drain line to merge into another
• Creates a gentle change in direction
• Keeps solids and liquids moving efficiently
• Because of the angled entry, wyes are preferred over tees in drainage systems.

Common Uses

• Connecting a sink, tub, shower, or floor drain into a main drain line
• Branching horizontal drains
• Vent connections (depending on code and orientation)
• Sewer and building drain piping

Simple Example

You have a 3" horizontal main drain and need to connect a 2" branch from a sink. You would use a 3" × 2" PVC wye so the sink drain enters smoothly.

Important Notes

PVC wyes are for drainage only, not pressure water lines
Must be installed with proper slope (typically ¼" per foot for small pipe)
Often paired with a 45-degree elbow to fine-tune direction