What is the primary function of a check valve in plumbing?

The primary function of a check valve in plumbing is to allow fluid to flow in one direction only. This is crucial in many plumbing systems as it prevents backflow, which can lead to contamination of the water supply, damage to pumps, and inefficient system operation. Check valves isolate sections of the plumbing and ensure that once water flows through a part of the system, it does not reverse direction, thus maintaining system integrity and safety.

By preventing reverse flow, check valves also help in maintaining proper system pressure and ensuring that pumps operate efficiently. This functionality is especially vital in sewage systems, irrigation systems, and any application where backflow could pose significant problems. Other elements like increasing water temperature, monitoring water quality, or regulating pressure are handled by other specific devices and do not relate to the function of a check valve.