Plumbing: The Minimum Size for Bathtub Trap and Trap Arm

What is the minimum size required for the trap and trap arm for a residential bathtub?

A. 1 inch

B. 1.5 inches

C. 2 inches

D. 2.5 inches

Answer:

The correct answer is B. 1.5 inches

In the world of plumbing, the minimum size for both the trap and trap arm for a typical residential bathtub is 1.5 inches in diameter. These components are crucial in the drainage system, as they play a vital role in preventing sewer gases from seeping into the home.

The trap and trap arm work together to create a seal that retains water and blocks the passage of unwanted odors and gases. The 1.5-inch diameter is specified by the International Plumbing Code to ensure that the trap can hold enough water to maintain the seal effectively.

Additionally, this sizing allows the trap and trap arm to accommodate the relatively high water flow rate typically seen in a bathtub. By adhering to these standards, plumbers ensure the proper functioning of the drainage system and the safety and comfort of the residents.

So, the next time you encounter plumbing work involving a residential bathtub, remember that the minimum size for both the trap and trap arm should be 1.5 inches in diameter to meet industry standards and ensure optimal performance.