The Tigris river water in this study was evaluated at three water treatment plants in Baghdad city for six months from January 27, 2019, to August 28, 2019, the water assessment has been done by using the Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI) for a total of 540 samples of 12 parameters and the parameters are Turbidity, Total Hardness as CaCO3, Chloride, pH, Sulfate, Total dissolved solids, Iron, Fluoride, Nitrite, Nitrate, Ammonia, Faecal Coliform. The calculated CCMEWQI for the three water treatment plants as signal station WQI were; Sharq Dijla (61.64726, marginal), Al Wathba (63.2286, marginal), Al Wihda (62.984135, marginal), and the calculated CCMEWQI for Tigris river passing through Baghdad city as multi-station WQI was (62.59553, marginal), the Tigris river passing through Baghdad city status is not promising since the water treatment plants on Tigris river in Baghdad city are already outdated. The CCMEWQI is calculated using MATLAB by developing a flexible and extraordinarily easy code for any types of parameters and guidelines and for any size of data.

Keywords : Water quality, Tigris, CMEWQI