In water supply systems, what is the function of a backflow preventer?

The role of a backflow preventer in water supply systems is crucial for maintaining the safety and quality of drinking water. A backflow preventer is designed specifically to prevent contamination of the water supply. It works to stop water from flowing backward in a plumbing system, which could occur due to changes in pressure. Such reverse flow could bring contaminated water from non-potable sources into the potable water supply, posing serious health risks.

By installing a backflow preventer, the integrity of the water system is protected, ensuring that clean and safe water is delivered to consumers. This device is especially important in systems where potential risks for backflow exist, such as in irrigation systems, industrial processes, and areas with multiple water sources. Therefore, the primary function of a backflow preventer is indeed to safeguard drinking water from contamination, making this answer the correct choice.