When should check valves be installed in a water system?

Check valves are designed to allow fluid (in this case, water) to flow in only one direction, preventing backflow. They play a crucial role in maintaining the integrity of the water system and safeguarding it against contamination from reverse flow. In the context of the question, the correct choice indicates that check valves should be installed when water is flowing in two directions. However, this is somewhat misleading, as check valves specifically prevent reverse flow.

In a typical water system, check valves are critical in applications where there is a risk of backflow, which can occur in systems with multiple sources or pressures. For instance, check valves are essential in preventing cross-connections between different sections of the system and ensuring water only moves through pipelines in the intended direction, ultimately protecting both the system infrastructure and public health.

The context for installation should actually focus on situations where backflow prevention is necessary, which typically implies the potential for flow in the reverse direction. In practical terms, check valves are installed in various scenarios involving pumps, to maintain unidirectional flow created by the operation of the pump and to prevent potential backflow during shutdown or failure scenarios.

While options involving pump operation and high pressure are also relevant to the functioning of the valves, the fundamental purpose of