The city of Salé produces about 24 millions m3/year of wastewater. The majority of this water is discharged directly into the Atlantic coast and Bouregreg estuary without any treatment. To preserve the quality of the receiving waters. treating wastewater and reusing it in agriculture proves very interesting. The objective of this study is thus to investigate the treatment and recycling of wastewater in agriculture. We are particularly interested in studying the growth of the stem and the average number of leaves in order to prove the positive effects of reusing treated wastewater in agriculture as compared to untreated wastewater. To achieve this objective. we have investigated the irrigation of the broad bean by three types of water: Untreated wastewater (UW). Well water (WW) and biologically treated wastewater (TW).