  Water vapor maser emission in the 6_{16}-5_{23} transition towards the
narrow-line Seyfert 1 (NLS1) galaxy NGC 4051 has been discovered during an
ongoing single-dish extragalactic water maser survey. The Doppler-shifted maser
components appear to bracket maser components lying near the systemic velocity
of the galaxy symmetrically. The tentative result of a Very Large Array (VLA)
snapshot observation is that the masers are confined within 0.1 arcsec (5 pc at
a distance D = 9.7 Mpc) of the radio continuum peak seen at 8.4 GHz. The low
luminosity of the maser (~2 Lsun) is not typical for masers that coincide with
the radio continuum nucleus and appear associated with Active Galactic Nucleus
(AGN) activity.
  A low-luminosity maser in a Type 1 Seyfert nucleus could be explained by a
low maser gain resulting from the lower inclination of an obscuring disk around
an active nucleus.
