This report represents the initiation of a program to determine the types of sources of priority pollutants and the magnitude of their contribution to publicly owned treatments works (POTW). The initial phase, described in this report, is designed to study the non-heavy industry contributors. Thus, residential, commercial and light industry-type sources have been identified as those of primary interest. The complete study is to be carried out in phases and this report describes the result of the first phase of the program which was designed to develop a general approach, obtain background information, test alternative procedures and develop the basis for detailed planning of the full study. A detailed quality control program was implemented for this study. A total of 69 composite samples were collected for the generation of 140 samples for analysis, the increment coming from the quality control program. Samples were analyzed for all 129 priority pollutants (excluding asbestos) plus manganese and the classical parameters of pH, TEMP, TSS, TOC, BOD, COD, ammonia, oil and grease. Approximately 20 organic species were detected in the POTW influent and sewer samples, mostly at concentrations near the detection limit. Only several organic species were found above 10 mg/l, namely chloroform and other halomethanes, phenol, toluene and naphthalene (each at one sewer site) and three phthalates.