The anti-siphon hole in a dip tube of a water heater tank is required to be located within ____ inches of the top of the tank.

The correct requirement states that the anti-siphon hole in a dip tube of a water heater must be located within 6 inches of the top of the tank. This positioning is crucial for ensuring proper functionality and safety in a water heating system. The primary purpose of the anti-siphon hole is to prevent backflow of water into the tank. If the hole were placed too far down, it could allow for siphoning, which could lead to contamination or improper heating. By placing the hole close to the top, the design helps maintain adequate pressure and prevents unwanted siphoning, making it an essential feature for the safety and efficiency of the water heater. This specification is rooted in building codes and standards, ensuring that water heaters operate safely and effectively.