Treated wastewater which comes from Adra Treatment Station is used for irrigating a part of the agricultural lands at Damascus Eastern Ghota after transferring it by a set of canals constructed for this purpose, Figure No. (1), its area estimated about 18000 hectares in addition to the adjacent areas for comparison object, the irrigated land by this project is forming the main study object of this research. This area is considered as the most affected area by the agricultural and industrial activities, increasing of population development due to its natural resources on one side and its location near the capital of Damascus on the other hand. The mean value of wastewater volume coming to the station has been estimated at 485000 m3 per day [1]. Therefore, this project is considered as one of the important projects which ensure an additional water resources for that area where water demand increased specifically against decreasing water resources of formerly years of aridity which considered as one of its reasons. From this point, this research is aimed at clearing out quality changes happened in the groundwater in the Eastern Ghota area which affected with irrigation by treated water, that was due to observing the quality changes of groundwater through a grid of wells and processing these analysis results by making maps, diagrams, and graphs; then comparing them with adjacent areas data, and to read out of these changes and reach knowledge of irrigation effect range by this water on the groundwater quality.