What is the required trap and trap arm size for a kitchen sink?

The required trap and trap arm size for a kitchen sink is typically 1 ½ inches in diameter. This size is important because it effectively accommodates the volume of wastewater that a kitchen sink may produce, especially considering the types of waste typically present, such as food particles and grease. A trap of this size helps to prevent clogs and enables proper drainage without creating excessive pressure within the plumbing system.

Larger sizes, such as 2 inches or 4 inches, may be used in systems requiring more capacity, such as sewage lines or for multiple fixtures, but they are not standard for a single kitchen sink. A 1 ¼ inch size is generally too small for a kitchen sink trap, potentially leading to drainage issues. Thus, a 1 ½ inch trap is the standard required size that balances effective drainage with the potential for clogging, making it the appropriate choice for a kitchen sink.