The objective of this American Water Works Association Research Foundation study is to determine the range of velocities andassociated boundary shears required to dislodge and remove various accumulated materials from water distribution mains. The physical processes affecting particles in a pipeline environment are precipitation, sedimentation, compaction, surface scale formation, solubilization, sloughing, re-suspension, and transport. This project focuseson the sloughing, re-suspension and transport processes. Common flushing practices often depend on visual appearance for the duration or velocity of flushing. This projectaims to relate the mechanisms of sloughing, re-suspension and transport of particles in distribution mains to specific flushing velocities. The variable affecting shear force required to dislodge a particle include flow velocity, density of the fluid, size and density of the particle, and pipe size and type. Particle transport is governed by entrainment and saltation. The relationship among these variables is being addressed in this study through a literature review, utility surveys, case studies, computational fluid dynamics modeling, pilot studies, and field studies. This paper discusses the results of the literature review and utility surveys. Includes 2 references, figures.