Apparatus and method of monitoring the level of a liquid medium in a container

An apparatus for monitoring of a level of a liquid within a container, such as a pet water feeder, said apparatus comprising: one or more permanent magnets embedded either within an attachment band 103 disposed on the exterior wall of the container, or in a float 102 disposed within said container and free-floating or immersed on said liquid. An electric circuitry comprising a battery, alerting unit and one or more magnetic proximity sensors are embedded complementarily either into the float disposed within said container and free-floating or immersed on said liquid or in the attachment band. The float moves laterally and vertically into and out of proximity of the attachment band, with variance of the level of the liquid, wherein the proximity of the float to the attachment band is sensed by the proximity sensors, when the float is in close proximity with the attachment band, thereby activating the alerting unit to notify a user/caregiver about possible depletion of liquid within the container. Also claimed is a medical infusion bag liquid medium level monitor, comprising: a flexible collapsible enclosure configured to contain a liquid medium; a first attachable part comprising at least one permanent magnet; and a second attachable part including an electric circuitry comprising a battery, at least one magnetic sensor, an alarming module and an actuation module; wherein said first attachable part and said second attachable part are disposed substantially diametrically opposite to each other, on exterior walls of said enclosure of said infusion bag, and wherein proximity of said first attachable part and said second attachable part is sensed by said at least one magnetic sensor of said second attachable part.