What is a common method to prevent backflow in plumbing systems?

Using check valves is a common and effective method to prevent backflow in plumbing systems. Check valves are designed to allow fluid to flow in only one direction, thereby preventing the reversal of flow that can lead to backflow contamination. This is critical in preventing unsafe or contaminant-laden water from flowing back into potable water supplies, which could pose health risks.

When installed correctly, check valves automatically close when the flow of water reverses, which effectively isolates sections of the plumbing system and mitigates the potential for backflow. This is particularly important in applications where water is drawn from various sources or where gravity might cause the reverse flow in the event of a pressure drop.

In contrast, installing a spigot, adding additional fixtures, or increasing pipe diameter do not inherently address the issue of backflow. A spigot primarily serves as an outlet for water but does not provide any backflow prevention. Additional fixtures may lead to increased complexity and potential cross-connection points without backflow protection unless properly equipped. Increasing the pipe diameter may improve flow rate or pressure but does not prevent backflow on its own. Thus, check valves remain the appropriate and standard solution for backflow prevention in plumbing systems.