  22 GHz water vapor emission was observed toward the central region of the
spiral starburst galaxy NGC 253. Monitoring observations with the 100-m
telescope at Effelsberg and measurements with the BnC array of the VLA reveal
three distinct velocity components, all of them blueshifted with respect to the
systemic velocity. The main component arises from a region close to the
dynamical center and is displaced by <1 arcsec from the putative nuclear
continuum source. The bulk of this maser component is spread over an area not
larger than 70 x 50 mas. Its radial velocity may be explained by masing gas
that is part of a nuclear accretion disk or of a counterrotating kinematical
subsystem or by gas that is entrained by the nuclear superwind or by an
expanding supernova shell. A weaker feature, located 5 arcsec to the northeast,
is likely related to an optically obscured site of massive star formation.
