Phytodepuration is one of the most widely used techniques for treating wastewater, thanks to its specific characteristic of simplicity of design. The main objective of this study is the treatment of domestic wastewater from a district in Nouakchott, using a macrophyte lagooning system. Several physico-chemical parameters were measured before and after treatment. Average abatement rates were recorded for biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and suspended solids (SS), with progressive acceptable values of 26.57%, 28.60% and 59.45%. Treatment efficiencies for nitrogen and ortho-phosphate (P-PO4) are generally low. In general, our results show that this natural lagoon achieves a good purification efficiency of organic pollutants, which indicates the importance of the role of purifying plants in reducing the organic and particulate pollutant load. As well as the role of the various substrates used in the experimental set-ups.