Empty drum detecting apparatus comprises an upright manifold chamber connected at its intermediate portion to a supply line extended to a supply drum of liquid chemical, and a pump for directing pumped liquid to process equipment utilizing the liquid chemical and having an inlet line. An outlet line is connected to the bottom portion of the upright manifold chamber and connected to the inlet line of the pump; and a shunt line with a flow restriction therein is connected between the upper portion of the manifold chamber and the outlet line for delivering collected gases and liquid to the inlet line and pump. An alternate flow restricting valve may be placed in the outlet line to restrict liquid flow from the lower portion of the manifold chamber. A capacitance proximity sensor is mounted above the inlet of the manifold chamber and senses the liquid level in the manifold chamber to produce an indication of the liquid level.