Using the diffusion quantum Monte Carlo (DMC) method with importance sampling, we calculate the binding energy and annihilation rate of positronium hydride, PsH. We get 1.0661 +/- 0.0014 eV for the binding energy, and 2.463 +/- 0.020 ns(-1) for the annihilation rate. The binding energy is in agreement with the results of the best Ritz variational calculations and the best DMC calculation reported to date, and the annihilation rate agrees with the results of the Ritz variational calculations but not that of the only other DMC result known to us. A new method for correcting expectation values calculated from mixed estimators is proposed and demonstrated.