Which maintenance practice helps in the prevention of cross-connections in a water distribution system?

The installation of backflow preventers is a vital maintenance practice for preventing cross-connections in a water distribution system. Cross-connections occur when there's a direct link between the potable water supply and a non-potable source, which can lead to contamination if backflow occurs. Backflow preventers are devices specifically designed to allow water to flow in one direction and prevent it from flowing backward into the drinking water supply. By ensuring that water only flows from the mains into the distribution system and not back from potentially contaminated sources, backflow preventers effectively safeguard the integrity of the water supply and protect public health.

Other practices such as annual water testing and frequent pressure monitoring are essential for overall system health and safety but do not directly address the issue of cross-connections. Regular valve replacement can help maintain proper functionality of the water distribution system, but it does not prevent backflow incidents from occurring. Thus, while all these practices are important, the installation of backflow preventers is the most direct and effective way to prevent cross-connections.