This paper investigated the effects of eight dissolved species concentrations on corrosion of carbon steel in water. Short term electrochemical experimental measurements indicated that the corrosion mechanisms of carbon steel in brackish water are uniform and pitting corrosion. The corrosivity of water is difficult to be defined using single parameter such as the corrosion rate. In this case Mahalanobis–Taguchi method as a discriminant analysis approach is applicable for water corrosivity assessment. Mahalanobis–Taguchi method enables to predict whether a given water sample is acceptably corrosive or not. The preliminary investigation has indicated that Mahalanobis–Taguchi method can serve as a tool for water corrosity assessment.