Similar to open quantum systems, the ensemble-averaged state of disordered quantum systems in general follows incoherent time evolution. Following this analogy, we can describe the dynamics of disordered systems in terms of quantum master equations. This approach allows us to access the full disorder-perturbed quantum state, both on the level of populations and coherences. As an example, we analyze the propagation of a particle in a disorder-perturbed waveguide. We quantify wave packet distortion, backscattering, and disorder-induced dephasing, and identify conditions for reliable quantum state transmission.