A waste coupling is a plumbing fitting used to connect a wash basin, sink, or bathtub outlet to the waste pipe (drain pipe). It helps drain wastewater smoothly from the fixture into the building’s drainage system.

Waste couplings are commonly made from:

• Brass

• Stainless steel

• Plastic / PVC

Applications

Waste couplings are used in:

• Wash basins

• Kitchen sinks

• Bathtubs

• Bathroom drainage systems.

Typical sizes used in plumbing:

• 32 mm

• 40 mm

• 3 inch / 4 inch (depending on the sink or basin type).