A connecting device for connecting a beverage machine with an external liquid delivery system, e.g. a water distribution network, to supply such liquid to said machine, said connecting device having: - an inlet for a fluid connection to said external system; - an outlet for delivering liquid from said external system via the inlet to said beverage machine; - a valve arrangement (12a,12b) switchable between an open configuration for establishing a fluidic connection between the inlet and the outlet and a closed configuration for interrupting the fluidic connection, such as a valve arrangement (12a,12b) comprising at least one valve (12a,12b); - a control unit for switching the valve arrangement (12a,12b) between its open configuration and its closed configuration; and - a sensor arrangement (15a,15b) connected to the control unit, the outlet being configured to deliver liquid from said external system into a tank of said machine or of such connecting device, the sensor arrangement (15a,15b) comprising a low level sensor for detecting a low level of liquid in said tank and a high level sensor for detecting a high level of liquid in said tank, characterised in that the control unit is configured to switch the valve arrangement (12a,12b) in response to a triggering signal from the sensor arrangement (15a,15b), and in that: - the low level sensor for detecting the low level of liquid in said tank is arranged to generate a triggering signal for switching the valve arrangement (12a,12b) to the open configuration so as to fill said tank with liquid delivered by the outlet; and - the high level sensor for detecting the high level of liquid in said tank to generate a triggering signal for switching the valve arrangement (12a,12b) to the closed configuration, and in that the control unit is also arranged to switch the valve arrangement (12a,12b) into the closed configuration: - when a predetermined period of time has lapsed after switching the valve arrangement (12a,12b) into the open configuration, the predetermined period of time being optionally user-adjustable, e.g. to adjust to a flow rate of liquid supplied from said external delivery system and/or to adjust to a maximum storage volume of said tank; and/or - when a further sensor provides a signal to the control unit that indicates that the high level has been exceeded. - an inlet for a fluid connection to said external system; - an outlet for delivering liquid from said external system via the inlet to said beverage machine; - a valve arrangement (12a,12b) switchable between an open configuration for establishing a fluidic connection between the inlet and the outlet and a closed configuration for interrupting the fluidic connection, such as a valve arrangement (12a,12b) comprising at least one valve (12a,12b); - a control unit for switching the valve arrangement (12a,12b) between its open configuration and its closed configuration; and - a sensor arrangement (15a,15b) connected to the control unit, - the low level sensor for detecting the low level of liquid in said tank is arranged to generate a triggering signal for switching the valve arrangement (12a,12b) to the open configuration so as to fill said tank with liquid delivered by the outlet; and - the high level sensor for detecting the high level of liquid in said tank to generate a triggering signal for switching the valve arrangement (12a,12b) to the closed configuration, - when a predetermined period of time has lapsed after switching the valve arrangement (12a,12b) into the open configuration, the predetermined period of time being optionally user-adjustable, e.g. to adjust to a flow rate of liquid supplied from said external delivery system and/or to adjust to a maximum storage volume of said tank; and/or - when a further sensor provides a signal to the control unit that indicates that the high level has been exceeded.