In 1984 the Delaware River Basin Commission and the National Park Service began a monitoring program to increase the frequency and areal extent of sampling within existing budget limitations. The goal of the program is to obtain water quality information on 120 miles of the Delaware River and 75 tributaries in a three-state area. This reach is included in the National Wild and Scenic Rivers System; recreation is intense. A variety of real and potential pollution sources exist. To maximize the available resources, a water quality screening approach was developed and put into practice via informal interagency cooperation. Parameters include rainfall, fecal bacteria, benthos diversity, and several chemical parameters. These are analyzed separately and compared between parameters and with adjacent watersheds. Experience has shown that the screening approach effectively assesses problems, sources of problems, and water quality management priorities. Small-scale research is also conducted and a feedback mechanism allows the program to adjust quickly to findings. The water quality screening approach applies to a variety of watershed and lake management situations and can augment traditional routine monitoring programs.