Groundwater in Iraq is considered to be an alternative water resource, especially for areas far away from surface water. Groundwater is affected by many factors including climate change, industrial activities, urbanization, and industrialization. In this study, the effect of artificial recharge on the quantity of groundwater in the Dibdibba unconfined aquifer in Iraq was simulated using a groundwater modeling system (GMS). The main raw water source used in the artificial recharge process was the reclaimed water output (tertiary treatment) from the main wastewater treatment plant (WWTP) in Kerbala, with 20 injection wells. After calibration and validation of the three-dimensional numerical model used in this study and taking wastewater recharge rates into account, two different scenarios were applied to obtain the expected behavior of the aquifer when the groundwater levels were augmented with 5% and 10% of the daily outflow production of the WWTP in Kerbala. The model matched the observed head elevations with R2 = 0.951 for steady state and R2= 0.894 for transient simulations. The results indicate that the injection of treated water through 20 wells raised the water table in more than 91 and 136 km2 for 5000 and 10,000 m3/day pumping rates, respectively. Moreover, increasing the volume of water added to the aquifer could lead to establishing new agricultural areas, spanning more than 62 km2, extending about 20 km along the river.