What protection is required for a connection between potable water supply and spa piping?

In the context of protecting the potable water supply from contamination when connected to spa piping, a vacuum breaker serves as a crucial safety device. It prevents backflow or back-siphonage, which can occur when there is a drop in water pressure in the supply line. If the pressure drops significantly, water from the spa can be sucked back into the potable water system, potentially contaminating it.

A vacuum breaker activates when a drop in pressure occurs, allowing air to enter the system and breaking the vacuum. This effectively stops contaminated water from flowing back into the clean water supply, ensuring that the drinking water remains safe and free from harmful substances. This protective measure is essential in commercial applications, such as spas and pools, where the risk of contamination is significant due to the chemicals used in maintenance and sanitation.

The other options, while they each serve important functions in plumbing systems, do not provide the specific backflow prevention that is needed for the connection between the potable water supply and spa piping in this particular scenario.