With the increase in water quality regulations and decrease in available fresh water supplies in the US, pressure-driven membrane processes are playing an increasingly important role in drinking water treatment. They are being employed to remove a wide range of contaminants, and depending on their use, can be operated with minimal or no chemical pretreatment that forms deleterious by-products. The major uses of membrane processes in the US include desalting, disinfection by-product control, disinfection, clarification and removal of synthetic and inorganic chemicals. Membranes are also furthering capabilities to purify wastewater for indirect potable reuse.