In this work, the validation of the method for the determination of chloride, nitrate and sulphate in potable drinking water and non-treated water was performed. The instrumental setup used was an automated ion chromatograph equipped with chemical suppression system for anion analysis. The significance of this paper falls on the statistical study of the analytical method, where all the uncertainty contributions involved in the process have been considered. Parameters such as repeatability, reproducibility, precision, accuracy, uncertainty, limits of detection and quantification, range of measurement and calibration figures of merit, were determined in this paper. (C) 2010 Elsevier B.V. All rights reserved.