What is the main concern when considering cross connections?

The primary concern regarding cross connections is their potential to lead to contamination of potable water. A cross connection occurs when there is a direct connection between a safe drinking water supply and a source of contamination, such as wastewater or chemicals. This scenario can create a pathway for harmful substances to enter the drinking water system, posing a serious health risk to consumers.

When pressure changes occur in the plumbing system, such as during a water main break or a sudden decrease in water flow, contaminated water can be siphoned back into the potable supply. This highlights the importance of implementing backflow prevention measures at these sites to ensure the safety and quality of drinking water is maintained. Ensuring that all plumbing systems are free from cross connections is a critical aspect of public health protection and water safety management.

The other options are not relevant to the main concern because they do not address the safety or health implications related to water quality. Instead, they relate to operational efficiency and performance characteristics of plumbing systems rather than contamination risks.