How must the fresh water supply line to the pool be configured?

The fresh water supply line to a pool must be configured to fill through an approved air gap to ensure that there is no possibility of backflow contamination from the pool into the public water supply. An air gap acts as a physical barrier that prevents any contaminated water from flowing back into the potable water supply due to backpressure or siphoning. This is a critical safety standard in both plumbing and public health regulations.

By utilizing an air gap, the risk of pollutants or pathogens from the pool water entering the fresh water supply line is effectively mitigated. This conforms to health codes and best practices designed to protect public health and ensure that the water supplied to the pool remains safe and free of contaminants.

The other configurations mentioned, such as a direct connection or utilizing a pump without proper backflow prevention measures, could violate safety regulations and pose a risk of contamination, making option B the most appropriate choice in ensuring safety and compliance.