Leisure vehicle with - a reformer-fuel cell system for an on-board supply; - a process water supply system for the reformer-fuel cell system, - a fresh water reservoir for storage of fresh water acting as process water for the reformer-fuel cell system, wherein the fresh water is a water that has not been recovered by condensation from a process of the reformer-fuel cell system; - a supply facility (3, 4, 5) for supplying the process water to the reformer-fuel cell system; and with - a water tank, which also acts at the same time as water tank of the leisure vehicle; wherein the fresh water reservoir is stored in the water tank of the leisure vehicle; - the water tank is connected to the supply facility (3, 4, 5) and to sanitary installations in the leisure vehicle, so that the water stored in the water tank can be used both as process water and as fresh water and service water for the sanitary installations; - a condensation device is provided for re-condensation of water contained in at least one of the fluid streams leaving the reformer-fuel cell system; and wherein - an operating mode changeover facility is provided, for switching between at least two operating modes of the following three operating modes: + supply of the reformer-fuel cell system with process water exclusively from the fresh water reservoir; + supply of the reformer-fuel cell system with process water exclusively from the condensation device; + supply of the reformer-fuel cell system with process water simultaneously from both the fresh water reservoir and the condensation device. - a reformer-fuel cell system for an on-board supply; - a process water supply system for the reformer-fuel cell system, - a fresh water reservoir for storage of fresh water acting as process water for the reformer-fuel cell system, wherein the fresh water is a water that has not been recovered by condensation from a process of the reformer-fuel cell system; - a supply facility (3, 4, 5) for supplying the process water to the reformer-fuel cell system; and with - a water tank, which also acts at the same time as water tank of the leisure vehicle; - the water tank is connected to the supply facility (3, 4, 5) and to sanitary installations in the leisure vehicle, so that the water stored in the water tank can be used both as process water and as fresh water and service water for the sanitary installations; - a condensation device is provided for re-condensation of water contained in at least one of the fluid streams leaving the reformer-fuel cell system; and wherein - an operating mode changeover facility is provided, for switching between at least two operating modes of the following three operating modes: + supply of the reformer-fuel cell system with process water exclusively from the fresh water reservoir; + supply of the reformer-fuel cell system with process water exclusively from the condensation device; + supply of the reformer-fuel cell system with process water simultaneously from both the fresh water reservoir and the condensation device. + supply of the reformer-fuel cell system with process water exclusively from the fresh water reservoir; + supply of the reformer-fuel cell system with process water exclusively from the condensation device; + supply of the reformer-fuel cell system with process water simultaneously from both the fresh water reservoir and the condensation device.