As a result of the physico-chemical determinations performed in the autumn of 2020 (21.09.2021) after pH (7.2-8.55) denotes class I water quality r. Răut in the limits of urban ecosystems Bălți and Florești. Oxygen regime indicators (CCO-Cr and CBO5) indicate the quality class between values II-V. After CCO-Cr water r. Răut corresponded to class II quality, and downstream of the discharge of water from the Biological Treatment Plant (SEB) Bălți as well as in the urban ecosystem (EU) Floresti class III quality. The CBO5 values for the N section of the Bălți urban ecosystem (EU) up to the confluence with the SEB fall into quality class II, downstream of this class III, and within the limits of EU Florești class V quality. Analyzing the evolution of the concentration of ammonium ions (NH4+) it can be seen that the values recorded were between (0.38-0.91 mg N/l), which corresponds to quality class II for surface waters. The water samples taken from Răut River in all research sites had a nitrite ion (NO2-) content of 0.036-0.12 mg / l corresponding to quality class II and III (good - moderately polluted). Quality class III was registered on the segment of the bus station and up to the confluence with the discharge of SEB Bălți. The concentration of nitrates (NO3-) was in class I quality (very good) for surface waters. According to the total phosphorus content (P tot), the water samples taken from the Răut river for most sites are classified as moderately polluted (quality class III). The content of 1.255 mg P/l was recorded in the water of the rowing lake, which corresponds to polluted waters or pollution class IV.