Abstract: Liquid level responsive apparatus is provided which includes a tube having a lower terminal end immersed in the liquid in a container uncovered when the liquid level is below the terminal end for discharge of air from the tube, the tube having a small electric motor driven air pump supplying air thereto, the tube having a pressure tap connected to one side of a diaphragm for normally maintaining the diaphragm in one control position, the diaphragm being collapsible to another control position, the tube having a vent of predetermined size for limited venting of air from the tube while the diaphragm is maintained in its one control position. The diaphragm can control a microswitch which in turn can control any desired operation such as shut-off of delivery. A plurality of tubes can be connected in parallel with their terminal ends in different liquid containers.