Which trap size is suitable for a residential kitchen sink?

For a residential kitchen sink, a trap size of 1 1/2 inches is suitable because it is the standard size for this application. The 1 1/2-inch trap effectively provides adequate drainage while maintaining the necessary seal to prevent sewer gases from entering the home. This size is specifically designed to handle the volume of water that a kitchen sink typically discharges, offering good performance in terms of flow rate and preventing clogging, which is essential for the high-use areas like kitchens.

Larger trap sizes such as 2 inches, 3 inches, and 4 inches may be unnecessarily large for a single kitchen sink and could lead to issues such as slow drainage or increased risk of siphoning. Additionally, local plumbing codes often dictate that a 1 1/2-inch trap is appropriate for sinks, reinforcing its effectiveness and compliance in residential plumbing applications.