What is the minimum trap size for a kitchen sink?

What is the minimum trap size for a kitchen sink?

• A. 1 1/2" Minimum Trap Size
• B. 2" Minimum Trap Size
• C. 1" Minimum Trap Size
• D. 3" Minimum Trap Size

Answer: (A)

In plumbing, the trap size must match the fixture’s flow to maintain the water seal and prevent siphoning while fitting the drainage system. For a kitchen sink, codes set a minimum trap diameter of 1-1/2 inches because a sink normally discharges more water than a lavatory and needs a trap that can handle that flow without losing the seal or clogging. A smaller trap would be undersized, increasing the risk of siphon, gurgling, or frequent clogs. A larger trap would work but isn’t required for typical residential use and adds unnecessary cost and space. So the minimum trap size for a kitchen sink is 1-1/2 inches.

In plumbing, the trap size must match the fixture’s flow to maintain the water seal and prevent siphoning while fitting the drainage system. For a kitchen sink, codes set a minimum trap diameter of 1-1/2 inches because a sink normally discharges more water than a lavatory and needs a trap that can handle that flow without losing the seal or clogging. A smaller trap would be undersized, increasing the risk of siphon, gurgling, or frequent clogs. A larger trap would work but isn’t required for typical residential use and adds unnecessary cost and space. So the minimum trap size for a kitchen sink is 1-1/2 inches.