A single-parameter model has been developed for the prediction of transient behavior of granular filtration. The model is based on the experimental finding that the collection efficiency has a characteristic dependency on an increase in the pressure drop caused by retained deposits. Practical correlations are established relating the histories of filter performance with the extent of deposit and other relevant variables. Tt is demonstrated that the predicted results agree well with the experimental data conducted to determine the changes in effluent quality and the pressure drop necessary for the specified flow rate.