What preventative measure can be utilized to protect against backflow in plumbing systems?

An air gap is an effective preventative measure for protecting against backflow in plumbing systems. It involves physically separating the supply pipe from the potential contamination source, creating a vertical distance between the two. This physical separation minimizes the risk of contaminated water flowing back into the clean water supply due to changes in pressure or siphoning effects.

Establishing an air gap is crucial, especially in scenarios where waste or hazardous substances could enter the water supply, such as in kitchen sinks, industrial processes, or irrigation systems. By ensuring that there is a significant distance between the end of the supply pipe and any potential source of contamination, the risk of backflow is greatly reduced.

While other methods such as regular inspections, velocity control, and pressure relief may contribute to the overall integrity and safety of plumbing systems, they do not provide the same level of direct physical separation as an air gap does regarding preventing backflow. Regular inspections help identify issues early, velocity control can influence flow dynamics, and pressure relief can address pressure conditions; however, none offers the same straightforward barrier to contamination that an air gap provides.