Drinking water pipe system, - with at least one cold water line and/or at least one hot water line, - with a sensor for measuring the water temperature in the cold water or hot water line and/or for detecting a drinking water withdrawal from the cold water or hot water line, wherein the sensor generates a sensor signal proportional to the measured water temperature and/or a detected drinking water withdrawal, wherein, when the sensor is designed to detect a drinking water withdrawal from the cold water or hot water line, the drinking water pipe system comprises a time measuring device and the sensor activates the time measuring device when a drinking water withdrawal is detected, and with a flushing cistern, in particular a concealed cistern, for a WC or urinal, the cistern being provided with the following accessories - with a drain valve which has a closure body which can be raised from a closing position into a flushing position, the closure body being designed as an overflow pipe and having a seal which, in the closing position, rests in a sealing manner on a valve seat, - with at least one water intake line (13, 14) which is connected to the cold water or hot water line, - with a valve arrangement for admitting drinking water present in the water intake line (13, 14), - with a water discharge line for discharging the drinking water admitted by the valve arrangement, and - with a control which generates a control signal for actuating the valve arrangement as a function of the sensor signal and/or when a predetermined time interval since a last detected drinking water withdrawal from the cold water or hot water line connected to the water intake line (13, 14) is exceeded, wherein the valve arrangement admits drinking water from the water intake line (13, 14) in dependence on the control signal, characterized in that the water discharge line is designed in such a way that. it discharges the drinking water admitted by the valve arrangement directly into the overflow pipe. - with at least one cold water line and/or at least one hot water line, - with a sensor for measuring the water temperature in the cold water or hot water line and/or for detecting a drinking water withdrawal from the cold water or hot water line, wherein the sensor generates a sensor signal proportional to the measured water temperature and/or a detected drinking water withdrawal, wherein, when the sensor is designed to detect a drinking water withdrawal from the cold water or hot water line, the drinking water pipe system comprises a time measuring device and the sensor activates the time measuring device when a drinking water withdrawal is detected, and with a flushing cistern, in particular a concealed cistern, for a WC or urinal, the cistern being provided with the following accessories wherein the sensor generates a sensor signal proportional to the measured water temperature and/or a detected drinking water withdrawal, wherein, when the sensor is designed to detect a drinking water withdrawal from the cold water or hot water line, the drinking water pipe system comprises a time measuring device and the sensor activates the time measuring device when a drinking water withdrawal is detected, and with a flushing cistern, in particular a concealed cistern, for a WC or urinal, the cistern being provided with the following accessories - with a drain valve which has a closure body which can be raised from a closing position into a flushing position, the closure body being designed as an overflow pipe and having a seal which, in the closing position, rests in a sealing manner on a valve seat, - with at least one water intake line (13, 14) which is connected to the cold water or hot water line, - with a valve arrangement for admitting drinking water present in the water intake line (13, 14), - with a water discharge line for discharging the drinking water admitted by the valve arrangement, and - with a control which generates a control signal for actuating the valve arrangement as a function of the sensor signal and/or when a predetermined time interval since a last detected drinking water withdrawal from the cold water or hot water line connected to the water intake line (13, 14) is exceeded,