Systems and methods for generating inerting gas on vehicles are described. The systems include a proton exchange membrane (PEM) inerting system, a pure water supply system configured to provide pure water to the PEM inerting system, wherein the pure water supply system is in fluid communication with the PEM inerting system to replenish water lost during operation of the PEM inerting system, and a recapture loop configured to direct at least one of moisture and water from an output of the PEM inerting system back into the PEM inerting system, wherein the recapture loop includes a water treatment system.