Illinois Plumbing Code Practice Exam 2025 - Free Plumbing Code Practice Questions and Study Guide

The minimum constant water service pressure requirement on the discharge side of the water meter, as stipulated by the Illinois Plumbing Code, is 20 p.s.i. This pressure level is essential for ensuring that residential and commercial plumbing systems can function effectively. It provides adequate pressure for fixtures to operate properly, preventing issues such as insufficient flow or inadequate performance in showers, faucets, and other water-using appliances.

Additionally, a pressure level at or above this minimum helps mitigate the risk of potential problems like water hammer or fluctuation that could arise if pressures were too low. The specified limit is a balance between providing sufficient force for normal usage while also being mindful of potential stress on the plumbing components.