A relief-valve pipe terminating into a water leak catch pan is not permitted because the pan is not __________.

A relief-valve pipe terminating into a water leak catch pan is not permitted because the pan is not classified as an indirect waste receptor. An indirect waste receptor is specifically designed to receive wastewater from a fixture, appliance, or equipment and allow it to discharge into the drainage system while preventing contamination or backflow into the potable water supply.

A catch pan, although it can capture leaks, does not properly convey waste to the drainage system in a way that maintains sanitary conditions. It lacks the proper design and functionality that direct drainage systems require, making it unsuitable for this purpose. By using an indirect waste receptor, the plumbing system ensures that any discharge is handled correctly, protecting both the sanitation and integrity of the plumbing installation.