The dangerous chemical contamination of the Sebou River Estuary by the untreated urban wastewater from the city of Kenitra has been the subject of an extensive and comprehensive characterization through the study of the physico-chemical qualities of effluent samples from eight different municipal wastewater collectors (A, B, C, D, E, F, G and H) using standard methods. The evaluated physico-chemical parameters include: flow rate, pH, temperature (T °), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended matter (SM) and electrical conductivity (EC). The characterization of the examined parameters displayed a moderately neutral pH level in the domestic wastewater collectors (B to H), nonetheless, collector (A) showcased an exceptionally alkaline pH that arrays from 8.1 to 9.6, which in turn impacts the electrical conductivity and temperature, to the point of occasionally reaching up to 30.3 °C in the collectorin question. Pertaining to the collected (COD) and (BOD5) results, their values significantly exceeded the Moroccan standards, especially in collectors A, G and F, exhibiting thus low biodegradability with a COD / BOD5 ratio exceeding 3. The characterization of municipal wastewater and the measurement of its flow made the estimation of the pollution quantity discharged at the level of the Sebou river estuary achievable, these data will subsequently be used in favor of modeling and monitoring the fate of pollution in the receiving environment.