The problem of liquid wastes is still current not only in Poland, but also in the world. The primary source of liquid wastes are single-family and multi-family houses. To a lesser extent, public service or production facilities, mainly in urban areas, are equipped with no-outlet reservoirs. Low concentrations in liquid wastes and their high density are often some difficulty to work with not only by sewage treatment plants, but also collection points. Therefore, the knowledge of the composition of liquid wastes supplied to the collection points is important. The paper presents the results of research as well as variability of concentrations of selected parameters of liquid wastes supplied to the collection point in Bialystok, that accepts both municipal and industrial sewage. Statistical processing of the obtained results and those derived from The Waterworks Bialystok showed the presence of high variability of total suspended matter and electrolytic conductivity as well as organic impurities expressed as BOD₅ and COD.