The reuse of treated wastewater can reduce the water deficit in Saharan areas, especially in Ghardaia. The M'Zab wastewater treatment plant (WWTP) is designed to treat wastewater by the natural lagoon system, and to reuse the treated water for irrigation of agricultural perimeters in order to contribute to sustainable development efforts in the region. Indeed the present work aims to search for the study of the possibility of reusing treated wastewater of M 'Zab in irrigation, to do this, we established and followed the evolution of the various physical-chemical and bacteriological analysis for two years (2013-2015), to study the effectiveness of biological treatment in the reduction of wastewater pollution, and then compare the results of treated water with national and international standards in the field of 'irrigation. The results showed that the treated water is considered as poor quality water is not usable only for some salt-tolerant species and on well-drained soil and leached, require additional treatments for ensured the quality of this precious resource.