Why are check valves important? What is the purpose of the check valve? If you need fluid to flow through a pipe in one direction, you can't do without them. Check valves are designed with a two-way system with openings that allow fluid to pass through. After the flow has passed, the valve closes to prevent backflow. Check valves can also close automatically if downstream pressure is excessive. Common uses of check valves: Water and waste pumping systems Water pipe Sewage treatment system Heating system Fire hose Marine and naval industries Oil and gas pipelines Flush toilet device There are many different types of check valves, including rotary check, lift check, piston check, and ball check.