This article presents the results of an investigation carried out on the Nilufer stream located in the southern part of Marmara region in Turkey 1999-2003. It evaluates water quality and proposes local requirements to prevent aquatic pollution problems. The study took into account the seasonal influences of point and non-point discharges on the organic pollution levels of the stream. The results indicated sub-standard water quality in most parts of the stream. Untreated domestic wastewaters, industrial discharges and agricultural activities contributed to the total annual organic loading. This study reveals the importance of construction, operation, maintenance and legislation of wastewater collection and treatment programmes, as well as the need for strict control of point and non-point nutrient loads for the preservation of the Nilufer stream's water quality. Appropriate strategies for the control of point and non-point pollution sources, amendments and enforcement of legislation should be developed.