The paper examines the behavior of particle detachment in deep bed filtration and the dependence of particle detachment on several filtration operating parameters. Theoretical analysis was carried out by considering the balance of various relevant interaction forces. Based on the results, experiments were conducted to study the effect of particle size, filter grain size, and headless gradient on particle detachment in deep bed filtration. In one set of experiments, the filter was operated at constant filtration rate in order to build up the headless across the filter bed continuously. In the other set of experiments, the filter in operation was allowed to experience a short period of flow shock (i.e., to be subject to a higher flow rate during this period). Both sets of experiments confirmed the dependence of particle detachment on particle size, collector gain size, and headless gradient (degree of filter clogging) of the filter, as predicted by the analysis.