A mobile sanitary device, comprising: - a bowl having an upper opening, - a freshwater tank which is connected to the bowl via a water conduit that supplies water from the freshwater tank to the bowl, - a wastewater tank which is connected to the bowl via a wastewater line that discharges the wastewater out of the bowl from a bowl outlet opening to the wastewater tank, - a first intermediate tank which is inserted into the wastewater line between the bowl outlet opening and the wastewater tank, wherein a first sensor for detecting a measured value characterising a status in the first intermediate tank is arranged on the first intermediate tank and wherein an electronic monitoring unit is provided which is in signal communication with the first sensor and comprises an electronic memory unit in which process data are stored which represent at least one setpoint value of an operational process of water discharge out of the bowl to the wastewater tank, and wherein the electronic monitoring unit further comprises an electronic comparator unit which is configured to compare the measured value from the first sensor with the setpoint value of the operational process and to output an error message if the measured value differs from the setpoint value, wherein there is a control unit which is configured to control a suction operation out of the bowl, in that - an underpressure is produced in the first intermediate tank, - the first intermediate tank is placed into fluidic communication with the bowl, - liquid from the bowl is sucked into the first intermediate tank, - the fluidic communication between the bowl and the first intermediate tank is closed, - an overpressure is produced in the first intermediate tank, and - the first intermediate tank is connected to the wastewater tank, and that the electronic comparator unit is configured to output an error message when a) the measured value from the sensor indicates an underpressure which is less than a setpoint underpressure, at an operating point at which an underpressure is being produced in the intermediate tank, or b) the measured value from the sensor indicates an underpressure time curve which falls more slowly than a setpoint underpressure time curve, at an operating point at which liquid is sucked out of the bowl into the first intermediate tank, and wherein the electronic comparator unit is configured to output error messages that differ from each other and - in case a) an error message is outputted which indicates that there is a leak in the first intermediate tank or a failure of a vacuum generator, - in case b) an error message is outputted which indicates that there is a blockage in the wastewater line between the bowl and the first intermediate tank. - a bowl having an upper opening, - a freshwater tank which is connected to the bowl via a water conduit that supplies water from the freshwater tank to the bowl, - a wastewater tank which is connected to the bowl via a wastewater line that discharges the wastewater out of the bowl from a bowl outlet opening to the wastewater tank, - a first intermediate tank which is inserted into the wastewater line between the bowl outlet opening and the wastewater tank, - an underpressure is produced in the first intermediate tank, - the first intermediate tank is placed into fluidic communication with the bowl, - liquid from the bowl is sucked into the first intermediate tank, - the fluidic communication between the bowl and the first intermediate tank is closed, - an overpressure is produced in the first intermediate tank, and - the first intermediate tank is connected to the wastewater tank, a) the measured value from the sensor indicates an underpressure which is less than a setpoint underpressure, at an operating point at which an underpressure is being produced in the intermediate tank, or b) the measured value from the sensor indicates an underpressure time curve which falls more slowly than a setpoint underpressure time curve, at an operating point at which liquid is sucked out of the bowl into the first intermediate tank, - in case a) an error message is outputted which indicates that there is a leak in the first intermediate tank or a failure of a vacuum generator, - in case b) an error message is outputted which indicates that there is a blockage in the wastewater line between the bowl and the first intermediate tank.