What is the purpose of a check valve in plumbing?

The primary purpose of a check valve in plumbing systems is to control the direction of fluid flow. A check valve is designed to allow fluid to flow in one direction only, thereby preventing backflow or reverse flow, which can lead to contamination of water supplies or damage to equipment. This directional control is crucial in maintaining the integrity of plumbing systems, such as preventing wastewater from flowing back into clean water lines.

While pressure relief, increased flow speed, and filtration are important aspects of plumbing systems, they are not functions served by check valves. Pressure relieving devices are specifically designed to manage excess pressure, flow speed is increased through the design of pipes and fittings, and impurities are filtered out using dedicated filter systems. Therefore, the role of a check valve is distinctly focused on ensuring that flow occurs in a single direction, protecting the system from unwanted backflow.