Traps shall not extend nearer to the floor than how many inches, except laundry trays or similar fixtures?

• A. 6
• B. 12
• C. 18
• D. 24

Answer: (B)

The main idea is that there is a required minimum height from the finished floor for traps to keep them accessible and to allow proper piping and venting. The rule sets this minimum at twelve inches, which makes it practical to install the trap and its associated trap arm and cleanout while leaving enough clearance for maintenance and for the cabinet or base to fit the fixture above. Laundry trays or similar fixtures are exempt because their deeper bases and different installation geometry mean the trap can operate correctly even if it sits a bit lower. If the trap were placed much closer to the floor, servicing would be awkward and the piping layout could be cramped or misaligned; placing it much higher than necessary creates unnecessary clearance and potential clearance issues with cabinets and fixtures.