Prediction of total acidity can be used in lieu of measured acidity and for quality assurance purposes. In order to test the accuracy of the prediction methods, we compared the measured hot peroxide acidity values (El) by three methods (E2, E3, and E4) of predicting total acidity. This study showed that improved prediction of total acidity can be achieved by considering the effects of pH on aluminum hydrolysis and sulfate speciation with respect to water quality.