What results from negative pressure in the distribution pipes of a potable water supply system?

Negative pressure in the distribution pipes of a potable water supply system can lead to backsiphonage. This phenomenon occurs when there is a drop in pressure within the water system that allows contaminants from the surrounding environment or from other systems connected via a cross-connection to be drawn into the potable water supply.

When negative pressure is present, it can create a vacuum effect, which can cause water to flow backward. This backward flow pulls potentially harmful substances into the drinking water supply, compromising its safety. Backsiphonage is a critical concern in plumbing as it poses health risks by introducing pollutants into the clean water supply.

The other terms are related to plumbing issues but do not directly result from negative pressure in the same way. Cross-connection refers to a physical connection between potable water and non-potable water, which can lead to backflow but isn't a direct effect of negative pressure. Water hammer is a shockwave caused by sudden changes in water flow, and pressure surge involves a rapid increase in pressure in the system, neither of which is directly associated with the concept of negative pressure leading to backsiphonage.