dispensing within a liquid dispensing and suctioning system is controlled by pinching a flexible tube with a spring - biased actuator . the system includes a slidable extension for pulling the actuator to open the tube to dispense liquid to a surface to be cleaned . the system is assembled with a tubular wand of a wet / dry suctioning system . the liquid dispensing outlet from the system is a slot from which liquid exits . that outlet slot is disposed near to the suction inlet slot of the suctioning system . a rib which is located between the dispensing outlet and the suction inlet contacts the surface being suctioned for assuring that liquid reaches that surface and is not sucked up in the suction nozzle inlet reaching the surface .