Ropool bathtub pumps shall be located above the ____ of the fixture trap.

The correct choice is based on the technical requirements regarding the installation of bathtub pumps, specifically ropool bathtub pumps, in relation to fixture traps. According to plumbing codes, including the International Plumbing Code, the pump must be located above the weir of the fixture trap.

The weir is the critical part of the trap that creates a water seal, preventing sewer gases from escaping into the dwelling while still allowing wastewater to flow through. If the pump were positioned below the weir level, it could break the water seal and allow harmful odors and gases to enter the living space. This placement ensures that the pump operates effectively, maintaining the safety and sanitary conditions required in plumbing systems.

By being above the weir, the pump can effectively manage wastewater and not compromise the function of the trap, which is designed to retain water for odor control. This location is a crucial consideration in plumbing design to ensure proper drainage and compliance with local plumbing codes.