Commercial surface water classification is preliminarily based on physicochemical analyses. The ecotoxicological analyses performed during the research confirm that bioassays can support traditional monitoring as a useful tool for preliminary assess and predicting environmental damage. The problem of contaminant migration into the aquatic environment is particularly important in highly industrialized and urbanized areas, wherein rivers are constantly exposed to pollution due to anthropogenic action and for which, in accordance with the Water Framework Directive (WFD) recommendations, it is necessary to achieve good status and potential of the waters. Taking into account the above provisions, the ecotoxicological potential of surface water samples from the Kłodnica River has been assessed. During the research we used a biotest battery composed of organisms which represent three trophic levels of aquatic ecosystems: Vibri fischeri, Daphnia magna, and Lemna minor. Also, we performed physicochemical on-site analyses. Estimated values of selected physical and chemical indicators confirm the poor state of the Kłodnica. However, high toxic effect was obtained only in a few analysed samples. Moreover, is worth noting that within the study we found a relationship between the high salinity of river water samples and the response of exposed bioindicators.