Abstract: A water supply tank apparatus comprises a tank adapted for receiving and storing water; a drain pipe adapted for draining the water from the tank; a fill pipe adapted for filling the tank; a drain shutter adapted for enabling and disabling the draining device; a water level sensor providing a shutter closer adapted for closing the drain shutter at a selectively adjustable low water level; a device for disabling water filling at a selected high water level; and a lever and chain arrangement for opening the drain shutter thereby enabling draining of the tank.