Which method is used to prevent backflow in plumbing?

Preventing backflow in plumbing is critical to ensure that non-potable water does not contaminate the potable water supply. The installation of a backflow prevention device is the most effective method for safeguarding against backflow. This device is specifically designed to allow water to flow in one direction and block any reverse flow that may occur due to changes in pressure within the system.

While using water filters, regularly flushing pipes, and keeping water lines under constant pressure can contribute to overall water quality and system maintenance, they do not specifically address the mechanics of backflow prevention. Water filters are meant to remove contaminants but do not prevent the physical occurrence of backflow. Regular flushing can help maintain water quality by removing stagnant water, but it does not ensure that backflow cannot occur. Keeping water lines under constant pressure can help reduce the risk of backflow but is not a foolproof method since variations in pressure can happen.

Overall, the installation of a backflow prevention device provides a reliable safeguard designed specifically for this purpose, making it the correct choice for preventing backflow in plumbing systems.