The detection of 22GHz water vapor emission from IC 342 is reported, raising the detection rate among northern galaxies with IRAS point source fluxes S100µm>50Jy to 16%. The maser, associated with a star forming region ∼10-15" west of the nucleus, consists of a single 0.5km/s wide feature and reaches an isotropic luminosity of 10–2L☉ (D=1.8Mpc). If the time variability is intrinsic, the maser size is ≲1.5x1016cm (≲0.5mas) which corresponds to a brightness temperature of >109K. The linewidth, luminosity, and rapid variability are reminiscent of the 8km/s super maser in Orion-KL. A velocity shift of 1km/s within two weeks and subsequent rapid fading is explained in terms of a chance alignment of two dense molecular clouds. Observations at 22GHz toward Maffei 2 are also reported, yielding a 5σ upper limit of 25mJy for a channel spacing of 1.05km/s.
galaxies: individual: IC 342, Maffei 2 - galaxies: starburst - ISM: molecules - masers - lines: ISM radio