Abstract: A water heater dip tube includes an elongated body having an inlet end and an outlet end. An inner volume is arranged within the elongated body. An anti-siphon orifice is arranged along the elongated body proximate the inlet end. The anti-siphon orifice extends through a wall of the elongated body. The dip tube further includes an elastomeric membrane secured to the elongated body. The elastomeric membrane is arranged in the vicinity of the anti-siphon orifice. The elastomeric membrane is operable to block fluid flow through the anti-siphon orifice when a pressure at the inlet end is greater than a pressure at the exterior of the dip tube adjacent to the anti-siphon orifice, and to allow fluid flow through the anti-siphon orifice when a pressure at the inlet end is less than a pressure at the exterior of the dip tube adjacent to the anti-siphon orifice.