This study has been done due to the raising importance of aluminum in drinking water from health point of view. Survey of Al+3 concentrations has been done in Tigris river, in the water purification plants and water supply network. These plants are the larger ones in the city ( unified right side plant, Al-Qubba plant, the old left side plant ( Al-Arabi restrict) and Al-Danadan complex project). Results revealed that the Al+3 concentration on the river (through Mosul city) ranged from 7-37μg/L. The plants have increased this concentration in raining times (turbidity increasing times) to about 25-50 μg/L (ppb), because of adding alum in its work. Water distribution network does not affect the residual Al+3 in this study. There was a correlation between Al+3 and temperature. Finally, it can be said that Al+3 concentration in drinking water is in the safe side according to several international health organizations if the plants do not add alum.
Keywords; Aluminum, drinking water, treatment plant, Tigris river.