Water quality deals with the physical, chemical and biological characteristics in relation to all other hydrological properties. Analysis of physico-chemical parameters of water is essential, to assess the quality of water for the best usage like irrigation, drinking, bathing, fishing, industrial processing and recreational activities. To identify the water quality of Dawmat El-Jandal Lake, the seasonally collected water samples were subjected to different analyses. The samples were collected from 2 discharging points (Drain's outlets) and 7 stations which covering the lake area. Samples were analyzed for the determination of temperature, transparency , turbidity , Total Dissolved Solids (TDS) , electric conductivity (EC) , pH , total alkalinity, sulphate, total hardness (Ca and Mg), ammonia-nitrogen, nitrite-nitrogen and nitrate-nitrogen. The results revealed that the combination of different environmental factors affected the water quality of Dawmat El-Jandal Lake which turned it into a hypersaline ecosystem. The water quality is affected by the location of the 2 discharging points (the drain 2 outlets) into the lake.