When using a check valve, what is its primary function?

A check valve's primary function is to prevent backflow in a plumbing system. This device allows fluid to flow in only one direction, thus avoiding potential issues caused by reverse flow, such as contamination or damage to the system components. By ensuring that water or other fluids do not flow backward, check valves maintain the integrity and efficiency of plumbing systems.

Other choices reflect different roles in plumbing. For instance, regulating temperature pertains to devices like thermostatic valves, which control the temperature of water. Controlling pressure involves pressure regulators or relief valves, which manage the pressure within pipes to prevent excess pressure that could lead to leaks or ruptures. Reducing noise is often achieved through various sound-dampening methods rather than with check valves. Understanding these distinctions highlights the specific, vital role that check valves play in plumbing systems.