Controlling nonpoint pollution from developed urban areas has generally been considered impractical. In basinwide studies of toxicants upstream of two new nutrient-sensitive drinking water reservoirs, 516 small urban subdrainage basins in eight North Carolina cities were analyzed in detail. Each subbasin's area and land use were determined and pollutant loading factors lbs/acres/yr) applied. Except for nutrients, urban nonpoint sources contributed more pollutants than urban point sources. Pollutants were not evenly distributed across these cities; one-third of the area contributed about two-thirds of each city's copper, lead, zinc, total phosphorus, and total suspended solids (TSS), and about one-half of the total nitrogen, total Kiedahl nitrogen (TKN), and chemical oxygen demand (COD). If small detention basins were installed to control runoff from this one-third of each city, about one-half of the lead and total suspended solids and one-third of the zinc and total phosphorus would be removed from runoff from the entire city.