CSLB Class B General Contractor's License Practice Exam

In which scenario would a pressure reducing valve NOT be necessary?

1. If the standing pressure is already low

2. If the building is far from the city supply hub

3. If the plumbing system is old

4. If the appliances require high pressure

The correct answer is: If the standing pressure is already low

A pressure reducing valve is primarily used to manage excessively high water pressure within a plumbing system to prevent damage to fixtures and ensure safe water flow. In the scenario where the standing pressure is already low, the need for a pressure reducing valve is eliminated. A low standing water pressure means that the water supply does not exceed the acceptable limits, and thus, there is no risk of over-pressurizing the plumbing system. In this case, the role of a pressure reducing valve would be redundant, as its purpose is to reduce pressure, not to create it. The other scenarios present conditions where a pressure reducing valve could be necessary or relevant. For instance, if a building is far from the supply hub, the pressure might vary significantly, potentially leading to high-pressure issues when the demand increases. An old plumbing system may have variable pressure issues due to wear and corrosion, necessitating a way to manage these pressures. Additionally, appliances that require high pressure might lead to the need for managing overall system pressure to ensure safe and effective operation. Thus, the first scenario distinctly stands out as one where a pressure reducing valve is not necessary.