What is the primary cause of backsiphonage?

The primary cause of backsiphonage is low water pressure. Backsiphonage occurs when there is a negative pressure in the water system that allows contaminants to be pulled back into the potable water supply. This phenomenon often happens during events like a sudden drop in pressure caused by a water main break, firefighting efforts, or the usage of large volumes of water.

When the water pressure drops, it creates a vacuum effect, which can draw water, including potential contaminants from neighboring sources, into the clean water supply. Understanding this principle is crucial for maintaining safe drinking water and preventing contamination from external sources. The other options, while they may involve water quality or pressure, do not directly lead to backsiphonage in the manner that low water pressure does.