a wetting agent injection system is shown according to the preferred embodiment of the present invention utilized with firefighting apparatus having a positive pressure pump . the purpose of the system is to automatically inject a wetting agent into the pump during its normal firefighting operation . the system is controlled by flow switches located on one or more discharge lines of the pump , by a float switch in the wetting agent supply tank , and by regulated air pressure in the wetting agent supply tank . when the flow switches detect water flowing and when the float switch does not detect an empty supply tank , they activate relays within the control box of the system , which in turn activate electric solenoid valves permitting wetting agent to be injected into the suction side of the pump . once in the pump , the wetting agent rapidly mixes with the water . the water treated with wetting agent penetrates better , reaching deeper into the material mass than untreated water can . adjustable metering valves at the point of injection are further provided for allowing different flow settings and wetting agent viscosities .