Low pressure microfiltration and ultrafiltration membranes are used for control of disinfection by-product precursors and removal of natural organic matter, color, taste and odor, hardness, iron, manganese, arsenic, and other organic and inorganic compounds. These source waters are often challenging for membranes, as various constituents in the raw water, such as high turbidity and/or high organics, can lead to increased membrane fouling. The object of this project was to investigate the interaction of water quality, pretreatment chemicals, pretreatment processes, membrane configurations, and membrane materials on the membrane performance. The findings of this study can be used as a guidance for the drinking water community to determine how to optimize the integration of MF/UF technologies into existing or new conventional treatment plants. This project was implemented in three phases: bench-, pilot-, and full-scale studies. - Executive Summary.