Concrete is one of the most widely used construction materials and the second most consumed material after water. Due to the global water crisis, researchers have been driven to explore alternative water sources as a means of reducing the reliance on potable water in construction activities. This research aims to use treated wastewater in the manufacture of ordinary concrete. Five concrete mixes were designed: a reference mix using potable water and four mixes incorporating treated wastewater with varying sedimentation periods (0 weeks, 1 week, 4 weeks, and 6 weeks). Treated wastewater replaced potable water in the preparation of sixty concrete cubes, each measuring 150 × 150 × 150 mm. Laboratory testing was conducted on the mixing water to quantify its salinity, suspended solids, and pH levels. The fresh concrete was evaluated through setting time and slump tests, whereas the hardened concrete was assessed for its mechanical performance through compressive and tensile strength tests. The results showed that increasing the proportion of treated wastewater reduced the initial setting time, accelerating the loss of workability. Similarly, the final setting time decreased with higher wastewater content, leading to faster concrete hardening. The viscosity test revealed that the time taken for a steel ball to fall through treated wastewater was approximately twice that in potable water. Slump test results indicated that concrete workability improved with longer sedimentation periods of the treated wastewater. Moreover, compressive strength slightly increased as the sedimentation period increased, while tensile strength results were comparable between the reference mix and treated wastewater mixes................... Key words: ................Concrete, Sewage Treated Water, Wastewater Treatment Plants, Compressive Strength, Concrete Mix, Viscosity Water.