A parametric-deterministic urban rainfall-runoff model is described. The model uses a parametric soil-moisture-accounting procedure to determine antecedent-moisture conditions and the Philip equation to compute infiltration. Kinematic-wave theory is used for deterministic routing of flows over contributing areas and through a branched system of pipes or natural channels or both, to the watershed outlet. An option is included in the model to calibrate the soil moisture and infiltration parameters using a modified-Rosenbrock optimization technique. The model is conceptually simple, but a set of model segments can be arranged easily into a network that will represent many complex drainage basins.