A full-dimensional quantum dynamical study is reported for the title reaction on the YZCL2 potential energy surface. The influence of reagent rotation on the dynamics is examined in detail. It is found that the rotational excitation of the HD reagent substantially enhances the rate coefficient for forming the H2O + D product, and plays an important role in determining the branching ratio at low temperatures. The theoretical results are compared with available experimental data for an integral cross section, thermal rate coefficients, and their corresponding branching ratios. Excellent agreement between theory and experiment is revealed for available thermal rate coefficients and its branching ratio. The agreement between theory and experiment for the integral cross section is also satisfactory. The study clearly shows that the YZCL2 potential energy surface is capable of producing "quantitatively" accurate results for the title reaction.