  We present the project of a VLBI study of the 22 GHz H$_2$O maser in a
prototypical low-mass protostellar system IRAS 16293-2422. The observation was
conducted to characterise the cause of the newly discovered enhanced maser
activity in the source and to study the source's ejection behaviour as traced
by maser emission. Single-dish monitoring and analysis of archival data
indicate that the activity of the H$_2$O maser in IRAS 16293-2422 has a cyclic
character and traces episodic ejection events in the source. A new maser flare
was recently discovered in a spectral feature that has never shown such a
significant increase in flux density before. The flare of this feature seems to
indicate the beginning of a new cycle of activity.
