The present invention describes an apparatus (1) for water supply and sanitary purposes, e.g. for allowing purification and either recycling of water or discarding of water, wherein the apparatus (1) comprises an on/off unit (2) comprising a battery (3) and a transceiver (4), and wherein the on/off unit (2) is activable by pushing an on/off knob (5) of the on/off unit (2) rendering the transceiver (4) to transmit a wireless signal to a control system to turn the apparatus (1) on respective off. Furthermore, the present invention also relates to an apparatus (1) for water supply and sanitary purposes, wherein the apparatus (1) is a shower device (1) comprising a handheld shower unit (9) having a magnetic valve (8), and also comprising a holder unit (10) for holding the handheld shower unit (9) when not being used, wherein a magnet (11) is arranged in the holder unit (10) or the handheld shower unit (9), and wherein an activation sensor (12) is provided in the holder unit (10) or in the handheld shower unit (9) so that the magnetic valve (8) is turned into an open position when the handheld shower unit (9) is removed from the holder unit (10), and wherein the holder unit (10) holds the magnetic valve (8) in a closed position when the handheld shower unit (9) is held by the holder unit (10) and not being used. Moreover, the present invention is also related to a handheld shower unit (9) for an apparatus (1).