  We present VLBI observations of the H$_2$O maser emission towards a selection
of massive young stellar objects (YSOs). In one of these sources,
IRAS20126+4104, the measured proper motions confirm that the water masers spots
are tracing the very root (around 100 AU) of a conical bipolar outflow emerging
near the position of the embedded YSO, and are an excellent tool to investigate
the structure and kinematics of the outflow/jet. We also present preliminary
results of a first epoch EVN observations of a selection of 5 high-mass YSO to
assess the precise association of maser spots and molecular outflows in these
sources.
