It is essential to monitor the evolution of pollutants including heavy metals found in water intended for irrigation. Since they have a crucial impact on living beings. In this study, the contents of heavy metals were analyzed by ICP-AES on the three levels of irrigation water, soil and plants (olive tree and cardoon) and those in four different terrains. The Cd, Cu and Pd found in the water of the downstream Oued Fès and the treated wastewater are out of the norm. We found Pd in higher concentrations in both plants. For Cu it is more assimilated by the olive tree. Regarding the soil, the content of Cr is very high in the plot irrigated by water from Oued Fès located downstream and less high in the plot irrigated by treated wastewater. The cardoon of this last plot present an increased concentration in Cr more than the others. These variations depend on the type of plants and their different characteristics of absorption according also to the accumulation of metals in the soil adding also anthropic factors.