What must support a soil stack, waste stack, or vent stack?

A soil stack, waste stack, or vent stack must be supported at its base to ensure stability and prevent movement due to the weight of the materials and the flow of waste. Proper support at the base helps maintain an upright position, minimizes the risk of bending or breaking under load, and ensures that connections to the plumbing system are secure and leak-free. Supporting these stacks at their base is a standard practice in plumbing to facilitate the safe and effective removal of wastewater and venting of gases from a building.

Options suggesting that the stack should be free-standing, suspended from the ceiling, or anchored to the wall would not provide the necessary stability and could lead to structural failures or inefficient plumbing performance. Properly supporting the stack at its base is crucial for compliance with plumbing codes and for the long-term functionality of the plumbing system.