At present no Macrophyte WSP system under study in many of developing countries like Pakistan, so for promotion of macrophytes based WSP system, detailed pilot scale studies is needed for treating wastewater that can be used for irrigation purposes. In near future, water scarcity is expected all over the world so efforts should be made to address this issue, as most of economy of our country is dependent on agriculture. The aims of this study is to reduce and evaluate the different parameters of domestic wastewater by treating it with macrophtes WSP system with different Hydraulic Retention Times (HRT) so that wastewater can be used for irrigation purposes as per FAO Irrigation Water Quality Guidelines. A macrophytes WSP system model was designed /operated for five experimental runs with each run comprising of different HRT i.e. 3, 5, 7 and 10 days. For treating wastewater, locally available Macrophyte specie Duckweed was used. The different parameters used in this study were; ECw , TDS, SAR, Sodium, Chloride, Boron, Nitrate, Bicarbonate, pH and F Coliform. The average reduction in values of different parameters of wastewater at the start of each run was 31.96%, 31.96%, 42.51%, 31.00%, 22.86%, 34.52%, 30.23%, 50.23%, 20.02% and 41.39% for ECw, TDS, SAR, Sodium, Chloride, Boron, Nitrate, Bicarbonate, pH and F Caliform respectively. After treating wastewater with 10 days HRT, the values of different parameters of wastewater was within the range of FAO guidelines with slight to moderate degree of restriction on use.