What is the purpose of a distribution system's backflow preventer?

The purpose of a distribution system's backflow preventer is to prevent water contamination. Backflow preventers are critical components of water distribution systems as they are designed to stop the reverse flow of potentially contaminated water back into the clean water supply. Contaminated water could arise from various sources, such as irrigation systems, industrial processes, or other connections that might introduce pollutants.

By ensuring that water can only flow in one direction, backflow preventers protect public health by safeguarding drinking water supplies from harmful pathogens, chemicals, and other hazardous substances. This is particularly important in maintaining the integrity of the water supply and complying with health regulations.

In contrast, the other options involve functions that do not align with the primary role of backflow preventers. Free flow of water pertains to unobstructed system flow, increasing pressure relates to pumps or pressure regulators, and monitoring flow rates is typically done through flow meters. None of these options directly address the backflow preventer's essential function of contamination prevention.