  We report the first systematic study of the submillimeter water vapor
rotational emission lines in infrared (IR) galaxies based on the Fourier
Transform Spectrometer (FTS) data of {\it Herschel} SPIRE. Among the 176
galaxies with publicly available FTS data, 45 have at least one H$_2$O emission
line detected. The H$_2$O line luminosities range from $\sim 1 \times 10^5$
$L_{\odot}$ to $\sim 5 \times 10^7 L_{\odot}$ while the total IR luminosities
($L_\mathrm{IR}$) have a similar spread ($\sim 1-300 \times 10^{10}
L_{\odot}$). In addition, emission lines of H$_2$O$^+$ and H$_2^{18}$O are also
detected. H$_2$O is found, for most galaxies, to be the strongest molecular
emitter after CO in FTS spectra. The luminosity of the five most important
H$_2$O lines is near-linearly correlated with $L_\mathrm{IR}$, no matter
whether strong active galactic nucleus signature is present or not. However,
the luminosity of H$_2$O($2_{11}-2_{02}$) and H$_2$O($2_{20}-2_{11}$) appears
to increase slightly faster than linear with $L_\mathrm{IR}$. Although the
slope turns out to be slightly steeper when $z\sim 2-4$ ULIRGs are included,
the correlation is still closely linear. We find that
$L_\mathrm{H_2O}/L_\mathrm{IR}$ decreases with increasing $f_{25}/f_{60}$, but
see no dependence on $f_{60}/f_{100}$, possibly indicating that very warm dust
contributes little to the excitation of the submillimeter H$_2$O lines. The
average spectral line energy distribution (SLED) of the entire sample is
consistent with individual SLEDs and the IR pumping plus collisional excitation
model, showing that the strongest lines are H$_2$O($2_{02}-1_{11}$) and
H$_2$O($3_{21}-3_{12}$).
