What is the purpose of a backflow preventer?

The purpose of a backflow preventer is to prevent contaminated water from flowing back into the potable water supply. This device is critical within plumbing systems, especially in situations where there is a risk that non-potable water sources can backflow into the clean water supply due to pressure changes, siphoning, or other disruptions in the system.

Backflow can occur when there is a drop in pressure in the potable water supply line, allowing water from a different source, which could be contaminated, to flow backward into the clean water system. This contamination poses serious health risks, which is why backflow preventers are installed in various applications, such as irrigation systems, industrial processes, and even in residential plumbing systems.

The other options focus on different aspects of plumbing systems. Reducing water pressure and regulating temperature are functions associated with different types of valves and devices but do not address contamination issues. Preventing leaking pipes is related to the containment of water within the system but does not prevent backflow, which is specifically concerned with the integrity of the potable water supply.