The main sources of pollution observed in the basin of the Oum Er Rbia are due to urban and industrial worn-out water dismissals and the agricultural activity notably the utilization of fertilizer and pesticides. The direct or indirect effect of these different sources of pollution result in deterioration of the resource quality in underground and superficial water.

Surface water quality is generally good in the upstream of the basin and it is degraded downstream as a result of urban or industrial discharges. The section situated between the downstream of Kasba-Tadla and downstream of Ouled Zidouh on the Oum Er Rbia Oued is especially polluted by the combined effect of the industrial and domestic discharges and experiences excessive deterioration during the summer months due to sugar production activities and other untreated discharges.

Groundwater quality is degrading continuously: the observed concentrations of nitrates observed evolved on the last fifteen years to reach worrying levels (concentrations over 50 mg/l for the majority of stations sampled). This fact adds to the elevated salt concentrations in certain water tables (Beni Amir, Beni Moussa West).