Using a recently developed superposition method, we consider resonant tunneling through a double-barrier structure in a resistive wire. The wire with finite mean free path permits phase-randomizing scattering; the barriers are described by elastic scatterers. We analyze in detail the evolving residual-resistivity dipole surrounding the barriers. We investigate the additional resistance due to the barriers and study the transition from completely coherent to completely incoherent transmission. The transport regime is governed by the ratio of the mean free path to the well width. We discuss the effect of phase-breaking scattering on the tunneling process leading to a decrease in the resonant transmission probability and a rise in the off-resonant one. A formula for the density of states in the well is also obtained.