What is the function of a backflow preventer?

The function of a backflow preventer is primarily to stop contaminants from entering the potable water supply. Backflow preventers are essential devices installed in plumbing systems to maintain the safety and quality of drinking water. They work by allowing water to flow in only one direction, preventing any reverse flow that could lead to contamination from sources such as irrigation systems, industrial processes, or sewage.

When there is a drop in water pressure in the system, without a backflow preventer, dirty water could be siphoned back into the clean supply, posing serious health risks. Therefore, the backflow preventer's role is critical in safeguarding public health by ensuring that potable water remains uncontaminated, which is why it is central to plumbing and water supply regulations.

Other choices refer to functions that are unrelated to the primary purpose of a backflow preventer: enhancing water pressure, regulating temperature, and filtering impurities are essential aspects of water management but do not pertain to preventing backflow in a plumbing system.