The study assessed the water quality of rivers in the Sebou basin in Morocco using a Water Quality Index and Geographic Information System. Results showed that 59% of monitored stations had bad or very bad water quality, with pollution mainly from phosphorus and ammonium. Some river sections are not safe for irrigation due to poor water quality. Water quality is better in the wet season compared to the dry season, likely due to industrial and domestic wastewater discharges and agricultural activities.