What is the function of the siphon breaker hole near the top of a dip tube?

• A. Siphon breaker hole near the top
• B. Direct cold water to the bottom
• C. Ventilation port
• D. Slow the water flow

Answer: (A)

That small hole acts as a siphon break. As cold water is sent down the dip tube to the bottom of the tank, a rapid flow can create suction that would try to pull hot water back up into the cold supply line. The hole near the top of the dip tube provides a tiny air intake when pressure differentials occur, breaking any siphon and preventing backflow into the cold supply. This keeps the hot water contained in the tank and maintains proper backflow protection. The dip tube itself is still delivering cold water to the bottom; the siphon breaker hole just stops siphoning, not by slowing flow or directing water differently.