  We report the first detection of thermal water vapor emission in the 557 GHz,
$1_{10} - 1_{01}$ ground state transition of ortho-H$_2$O toward VY Canis
Majoris. In observations obtained with the Submillimeter Wave Astronomy
Satellite (SWAS), we measured a flux of $\sim 450 $Jy, in a spectrally resolved
line centered on a velocity $v_{LSR} = 25 $km s$^{-1}$ with a full width half
maximum of $\sim 35$ km s$^{-1}$, somewhat dependent on the assumed line shape.
We analyze the line shape in the context of three different radial outflow
models for which we provide analytical expressions. We also detected a weaker
557 GHz emission line from W Hydrae. We find that these and other H$_2$O
emission line strengths scale as suggested by Zubko and Elitzur (2000).
