To assess urban storm-water-quality characteristics in the metropolitan area of Portland, Oreg., seven drainage basins were selected with varying drainage areas, basin slopes, impervious areas, land uses, and active construction areas. Automatic water-quality samplers, rain gages, and stream gages were installed in each basin. From September 1, 1975, to may 1, 1976, data were collected to determine rainfall intensities and define discharge hydrographs. Almost 500 samples from the seven basins were analyzed to describe pollutographs for at least four complete storms on each of the basins. In addition to the storm samples, several base-flow samples were collected and analyzed for each site.