As a hydrogen storage method for fuel cell vehicles, sodium borohydride (SBH), which does not emit carbon dioxide at the time of hydrogen generation, attracts attention. This material reacts with water and generates hydrogen and heat. Theoretically, the amount of the water generated by the FC is twice the amount required for the hydrolysis reaction of SBH. In other words, if it is possible to recover more than half of the generated water in the theory, no additional water is required for the hydrogen generation from SBH. In order to recycle the water for the hydrolysis reaction of SBH, it is necessary to estimate amount and state of the water exhausted from the cathode in FC stack. FC system has the complicated material balance of the water. In this study, considering the material balance of the water, a steady state model for the exhausted water in liquid state from the cathode in an FC stack was constructed. Using this model, parameter dependency for the amount of the recovered water in liquid state can be clarified. In this paper, the amount of the water estimated from the model and the measured amount were compared; and the validity of the model was verified. As a result, although there is the estimated error, parameter dependency for the amount of the recovered water in liquid state could be confirmed.