Whirlpool or Jacuzzi tubs require a minimum size drain line?

• A. 1 inch
• B. 2 inch
• C. 1 1/2 inch
• D. 1 1/4 inch

Answer: (C)

Drain sizing is about moving water away from the fixture efficiently and with proper venting. Whirlpool or Jacuzzi tubs act like larger bathtubs, so their waste line must be big enough to handle the water volume, especially when the tub is in use. The standard minimum for a bathtub waste line is 1-1/2 inches, which provides adequate flow and reduces the risk of slow drainage or clogs. A line smaller than that would clog more easily, while an oversized 2-inch line isn’t typically required for a residential tub and adds unnecessary cost. So the minimum drain line size for these tubs is 1-1/2 inches.