What condition can lead to backflow in a distribution system?

Backflow in a distribution system occurs when water flows in the opposite direction from its intended path, which can pose a significant risk of contamination. A vacuum or negative pressure condition in the system is one of the primary causes that can lead to backflow. When a vacuum forms within the water distribution system, it creates an area of low pressure. This low pressure can cause the water to be drawn back from consumers’ taps or other parts of the system into the distribution mains, effectively reversing the intended flow of water.

This situation is particularly dangerous because it can introduce contaminants from the distribution system or from other sources, such as service connections or connected plumbing, back into the clean water supply. Maintaining proper pressure throughout the system and implementing backflow prevention measures is crucial in safeguarding water quality and preventing contamination.