Studies were carried out in 2016 on a water outflow from a sewer drain, in the city of Stalowa Wola located in south-eastern Poland. The research material was collected from sediments being accumulated on the asphalt on which the water was flowing. Water from the studied outflow was characterized as alkaline to strongly alkaline pH (7.9–9.8), high to very high content of chlorides and sodium ions, and high electrolytic conductivity (331–13 250 µS cm-1). In the analyzed material, an unknown species of Stauroneis was found. The aim of this paper is to give a morphological and ecological description of Stauroneis saprophila sp. nov. from an anthropogenic environment.