Potable water is one of the main sources for the sustainability and development of human life. The current study aimed to assess the hydrochemistry of water in the unified Kirkuk water project (as it supplies the neighborhoods of the city with drinking water) for the dry and wet season (2019-2020) and the efficiency of the plant in water purification. Eleven samples were collected for the dry and wet season (W1-W11) from raw water, before adding alum, after adding alum, sterilization basin, ground tanks and tap water. The major and minor elements (Ca+ 2, Mg+2, Na +, K +, HCO3-, SO4-2, Cl-, NO3-) were analyzed respectively. The chemical and physical properties are measured which include pH, electrical conductivity, total dissolved solids (TDS), and turbidity. The results showed that they are in conformity with the specifications of the World Health Organization and the Iraqi Standard Specifications for the two seasons (dry and wet), except for the turbidity concentration in raw water for the two seasons, which was higher than the permissible limits due to weathering and erosion of geological layers as well as washing of agricultural lands and soils with rainwater. The application of the Water Quality Index indicated that the raw water samples were not suitable for drinking as they were classified under the category (unsuitable water), while the treated water samples were classified under the category (good water) for the dry and wet seasons.