What is the potential consequence of a backflow event during a water main break?

A backflow event during a water main break can result in contaminated drinking water supply due to the reversal of water flow in the plumbing system. When a water main breaks, the sudden drop in water pressure can create a vacuum effect that draws water from connected pipes back into the main supply line. If any contaminants are present in the drainage systems, such as sewage or agricultural runoff, there is a significant risk of these pollutants entering the potable water supply. This not only compromises the safety of drinking water but also poses serious health risks to the public.

The importance of backflow prevention devices, such as check valves and air gaps, becomes clear in this context, as they are designed to prevent such dangerous events from occurring. Ensuring that the water supply remains uncontaminated is critical for public health and safety.