Embodiments of the present invention provide a grey water flush system for use with vacuum toilets. One embodiment of the system provides a two-stage flush that uses a transient tank in between the toilet bowl and the main aircraft waste tank, which reduces the noise level associated with the flush process because a lesser vacuum is demanded for the first stage of the flush. Embodiments of the system further capture grey water from a sink basin in a reservoir and use that water in the toilet flush process. There is further provided a lavatory odor removal system option that is activated during the second stage of the flush.