What is a backflow prevention device installed to do?

A backflow prevention device serves a crucial role in protecting the drinking water supply from contamination. Specifically, it is designed to prevent the reverse flow of water in a plumbing system, which can occur when there are changes in pressure. When water in a system is pressurized, if the pressure drops suddenly, there is a risk that contaminated water could flow back into the clean water supply.

The function of this device is to maintain the integrity of the water distribution system by ensuring that water flows only in the intended direction—typically from the water main into a home or building, and not in reverse. This is essential for maintaining public health and safety by preventing potential contamination of potable water sources.

Therefore, the correct option highlights that backflow prevention devices are specifically targeted to manage the hydraulics of the customer's water system, ensuring that the flow direction is controlled and that clean water is not compromised.