Disinfection of Coxsackievirus B5 and Adenovirus 2 was modelled using Bayes nets. Interpolation of pH and turbidity values was possible through a Bayesian multilayer perceptron model. The combined effects of pH and turbidity on disinfection performance were assessed. Prediction of target CT and log reduction values for various scenarios could be obtained. Individually, pH had a higher impact than turbidity on target CT values.