What is the function of a backflow preventer?

The function of a backflow preventer is to prevent water from flowing backward into the potable water supply. This is crucial for maintaining the safety and cleanliness of drinking water. Backflow can occur due to a variety of reasons, such as a sudden drop in water pressure in the supply line, which can allow contaminants from non-potable sources to enter the clean water system. By installing a backflow preventer, the system ensures that water flows in only one direction – from the clean water supply to the end-users – effectively safeguarding public health from potential pollutants and toxins.

The other choices, while they pertain to water systems, do not describe the role of a backflow preventer accurately. Increasing water pressure is typically managed by pumps or pressure regulators, filtering sediments is done by filtration systems, and adding chlorine is part of the disinfection process to eliminate pathogens, none of which relate to the prevention of backflow.