Abstract: This invention is a constant head gravity fluid dispenser that guarantees a constant preset condition of its internal float valve (16) mechanism by encasing it in a reservoir (1) and also shielding it with a back-washable filter unit (9) that respectively ensures its physical insulation from external influence and any potential blockage. However, all minute particles pass through the filter aggregate at a predetermined location within the system to be drained. The dispenser engages a float mechanism, valves of different sizes and a vent pipe (11) attached to the reservoir (1) to exhaust excess internal air pressure as the reservoir is being filled.