  We report new Atacama Large Millimeter/Submillimeter Array (ALMA)
observations of a circumstellar disk around Source I in Orion KL, an archetype
of massive protostar candidate. We detected two ortho-H$_{2}$O lines at 321 GHz
($10_{2,9}$-$9_{3,6}$) and 336 GHz ($\nu_{2}=1, 5_{2,3}$-$6_{1,6}$) for the
first time in Source I. The latter one is in vibrationally excited state at the
lower state energy of 2939 K, suggesting an evidence of hot molecular gas close
to Source I. The integrated intensity map of the 321 GHz line is elongated
along the bipolar outflow while the 336 GHz line map is unresolved with a beam
size of 0.4\arcsec. Both of these maps show velocity gradient perpendicular to
the bipolar outflow. The velocity centroid map of the 321 GHz line implies
spatial and velocity structure similar to that of vibrationally-excited SiO
masers tracing the root of the outflow emanating from the disk surface. In
contrast, the 336 GHz line is most likely emitted from the disk midplane with a
diameter of 0.2\arcsec (84 AU) as traced by a radio continuum emission and a
dark lane devoid of the vibrationally-excited SiO maser emission. The observed
velocity gradient and the spectral profile of the 336 GHz H$_{2}$O line can be
reconciled with a model of an edge-on ring-like structure with an enclosed mass
of $>$7$M_{\odot}$ and an excitation temperature of $>$3000 K. The present
results provide a further evidence of hot and neutral circumstellar disk
rotating around Source I with a diameter of $\sim$100 AU scale.
