What is the purpose of a backflow preventer?

The purpose of a backflow preventer is to prevent polluted water from returning to a potable source. This device is crucial in maintaining the safety and quality of drinking water by ensuring that in the event of a pressure drop in the water supply system, contaminated water from non-potable sources cannot flow back into the clean water supply.

Backflow can occur due to various reasons, such as a sudden drop in pressure, which may happen during maintenance activities or pipe breaks. When such an occurrence happens, a backflow preventer stops any reverse flow that could potentially bring harmful pollutants or contaminants back into the drinking water distribution system. This is particularly important in areas where there may be a risk of contamination from sources like irrigation systems, industrial processes, or wastewater systems.

The other options do not accurately represent the function of a backflow preventer. For instance, increasing water pressure or maintaining water temperature do not relate to the purpose of preventing contamination. Monitoring water flow relates to measuring water usage rather than preventing backflow, making those options relevant but not correct in this context.