Abstarct: Water scarcity, the growing trend of population, and urbanization development in Iran has necessitated the planning for optimal use of conventional and unconventional water resources. Accordingly, it is possible to reuse treated wastewater under such circumstances, as one of the ways to overcome the water scarcity problem and prevent wastage of water resources. Torbat Heydariyeh Wastewater Treatment Plant was operated in 2009 with treatment process of activated sludge type. Wastewater treatment is being carried out in three stages of physical treatment, biological treatment, and disinfection and the resulted effluent (treated wastewater) is used for agriculture, horticulture, and industry. Given the release and use of effluent in the Roshtkhar plain aquifer, the present study was aimed to investigate the quantitative and qualitative effects of the effluent of Torbat Heydariyeh Wastewater Treatment Plant on groundwater resources. For this purpose, the physical, chemical, and biological properties of Torbat Heydariyeh effluent and groundwater resources were measured and evaluated over a one-year period. The measured parameters were major ions, electrical conductivity, pH, nitrate, heavy mextals, biological oxygen demand, chemical oxygen demand, and coliform bacteria. Consequently, examining the discharge time series (hydrographs) of qanats indicated an increased discharge or regeneration of some qanats after the operation of the treatment plant, highlighting the quantitative effect of effluent on groundwater resources. In addition, the values of major ions and heavy mextals in groundwater resources have been increased compared to the effluent, although the concentration of organic matter has been decreased significantly, which can be attributed to the impact of the unsaturated zone on the quality of the passing effluent. Finally, the results confirmed the evident effect of soil treatment mainly on the organic matter constituents of the effluent.