What is the purpose of a pressure relief valve in plumbing systems?

The purpose of a pressure relief valve in plumbing systems is to prevent pressure buildup. These valves are crucial safety devices designed to release excess pressure within a system, thereby protecting pipes and other components from potential damage caused by overpressure. When the pressure within a system exceeds a predetermined level, the pressure relief valve automatically opens to allow water or steam to escape, thus lowering the pressure to a safe level. This mechanism helps prevent catastrophic failures, such as pipe bursts or even explosions in extreme cases.

Options that suggest increasing water pressure, regulating temperature, or filtering impurities do not align with the intended function of a pressure relief valve. Their functions pertain to different aspects of plumbing and water management, which are not the focus of a pressure relief valve's role within the system.