When is it permissible to install a circulation pump for a whirlpool tub below the fixture trap?

In plumbing practices, the positioning of a circulation pump for a whirlpool tub is crucial for ensuring proper drainage and preventing backflow or contamination. Installing the pump below the fixture trap is generally not permissible because it can lead to various issues, such as siphoning water from the trap, which is designed to prevent sewer gases from entering the home and maintain a water barrier.

By keeping the circulation pump above the fixture trap, it avoids creating a situation where the pump could inadvertently remove the water seal from the trap. Any configurations that might compromise this essential function or potentially allow wastewater to flow back into the system are disallowed to maintain safety and sanitary conditions.

This approach conforms with standard plumbing principles and ensures compliance with the Omaha Plumbing Code, which prioritizes health and safety. Thus, the rule against installing a circulation pump below the fixture trap aligns with these principles, making it permissible never to position it in that manner.