What is the typical drain size for a kitchen sink?

The typical drain size for a kitchen sink is 1.5 inches, as this diameter is generally sufficient to handle the waste and drainage needs of a kitchen. Kitchen sinks typically see a variety of substances being drained, including food particles, grease, and water, which require an adequately sized opening to facilitate proper drainage and prevent blockages. A 1.5-inch drain allows for enough flow capacity to handle these demands without being overly large, which could create issues with waste retention or improper sealing.

While drains of different sizes exist for various applications, common household plumbing practices dictate that 1.5 inches is optimal for kitchen sinks, as larger sizes could lead to problems with installation compatibility and unnecessary costs. In contrast, smaller sizes like 1 inch may not provide sufficient drainage capacity, especially in busy kitchen environments where water flows continuously. Similarly, drains sized at 2 inches or 3 inches, while used in other plumbing contexts such as for larger fixtures or main waste lines, are not standard for kitchen sinks and could complicate fixture connections.