When a bypass is installed around a RPZ _______________________ is required?

When a bypass is installed around a Reduced Pressure Zone (RPZ) backflow preventer, it is crucial to ensure that the system meets the demands of maintaining proper backflow protection. Installing a RPZ on the bypass serves to protect the potable water supply by ensuring that any potential backflow hazards are effectively mitigated, even when the main RPZ is not in operation.

The RPZ is specifically designed to prevent contaminants from entering the drinking water supply under varying pressure conditions that could lead to backflow. Therefore, having another RPZ on the bypass ensures that there is a second line of defense against backflow from the potentially contaminated water within the bypass line. This aligns with the overall purpose of backflow prevention devices to safeguard public health by preventing the intrusion of pollutants into the water supply.

Other options, although related to safety and control measures, do not specifically fulfill the requirement laid out by plumbing codes regarding bypass configurations around RPZs. For instance, while a lockable valve may enhance security and control the system, it does not directly address the necessity of having additional backflow prevention. Similarly, while a ball valve is a common type of valve used in plumbing systems for controlling flow, it does not provide the necessary backflow protection required in this