DDSWMM is a stand alone model which includes the simulation of the rainfall-runoff process, flow routing, storage analysis, etc. It does not, however, simulate water quality. It can also be interfaced with the EXTRAN model for the analysis of complex sewerage systems.

DDSWMM has four main sub-components:

In addition, DDSWMM has sub-models for the design/analysis of storage facilities for the purpose of runoff control.