Why install a vacuum breaker on a electric water heater?

A vacuum breaker is installed on an electric water heater to prevent the risk of backflow, which can occur when a sudden drop in water pressure creates a vacuum in the system. This device protects the water supply from contamination by ensuring that water cannot siphon back from the heater into the potable water supply. Additionally, it helps to safeguard the water heater from potential damage caused by negative pressure conditions. Overall, a vacuum breaker enhances the safety and reliability of the water heating system.