What is one common reason for backflow to occur in a water system?

Pressure fluctuations in the supply line are a significant cause of backflow in water systems. When there is a sudden drop in pressure within the water supply lines—perhaps due to a large demand on the system, a burst pipe, or a significant reduction in flow—this can create a vacuum effect that allows water from the distribution system or even contaminated sources to flow backward into the potable water supply. Such fluctuations can disturb the normal flow and create conditions conducive to backflow, posing a risk to public health and safety.

Understanding this mechanism is crucial for maintaining the integrity of water systems, as it highlights the importance of ensuring consistent pressure and employing backflow prevention methods where needed.