DWV fittings are essential components in a plumbing system’s drain, waste and vent (DWV) network. Unlike supply piping, these fittings are designed for gravity‑driven flow and venting rather than pressurized water delivery. They join pipes that remove wastewater and facilitate air circulation so that drains operate smoothly and traps retain their water seal.

Materials and Design

DWV fittings are typically made from corrosion‑resistant materials such as PVC, ABS or cast copper. They feature smooth interior walls and sweeping bends to maintain flow velocity and reduce clogs. Sanitary tee fittings, wyes and long‑radius elbows provide gentle transitions so waste and air can move freely without creating pressure build‑ups. Because these fittings are not pressure‑rated, they should only be used in non‑pressurized drain applications.

Advantages

• Lightweight and easy to install: Plastic DWV fittings are light enough for one‑person installation and connect quickly with solvent cement or mechanical couplings.
• Chemical and corrosion resistance: DWV systems are exposed to household waste and cleaning agents; the materials used resist corrosion and many chemicals found in wastewater.
• Smooth flow: The interior surfaces are designed to minimize friction and accumulation, helping to prevent blockages and maintain trap seals.

Installation Tips

Always use DWV fittings in accordance with local plumbing codes. Ensure that each fitting is oriented correctly to maintain proper slope and venting. Because these fittings are not rated for high pressure, never substitute them for potable‑water pressure fittings. For pressurized applications, choose fittings specifically rated for supply pressure.