Water Distribution Grade 1 Certification Practice Exam

What kind of pressure must be maintained to prevent contamination from cross-connections?

1. Negative pressure

2. Positive pressure

3. Atmospheric pressure

4. Variable pressure

The correct answer is: Positive pressure

Maintaining positive pressure is crucial in water distribution systems to prevent contamination from cross-connections. A positive pressure within the water distribution system ensures that water flows toward the service connections and helps to prevent any backflow of water that could introduce contaminants from non-potable sources. When the pressure in a system is positive, it reduces the risk of siphoning or back-siphonage, which can occur when there is a drop in pressure within the system, allowing potentially contaminated water to be drawn back into the potable supply. In practical terms, a positive pressure acts like a barrier, maintaining the quality of the water by ensuring that any potential contaminants are kept at bay. In contrast to this, negative pressure can create conditions conducive to contamination. Atmospheric pressure is not sufficient to ensure that water remains uncontaminated, and variable pressure does not provide a consistent safeguard. Thus, establishing and maintaining positive pressure is a critical operational parameter in safeguarding water quality and ensuring public health.