The Surface Water Treatment Rule (SWTR) requires the reduction of turbidity and removal or inactivation of Giardia lamblia cysts, coliform bacteria and viruses by a treatment process consisting of a combination of filtration and chemical disinfection. The Memcor CMF microfiltration system consistently and reliably produces a finished water which exceeds the filtration requirements despite significant changes in feed water conditions. Minimal operator involvement is required as filtrate quality is obtained without conditioning of the feed. In addition to achieving the filtration requirements, microfiltration systems are able to achieve primary disinfection of the water through mechanical retention of coliform bacteria. Microfiltration can provide a unique "multiple barrier" approach to improve microbiological aspects of water quality. Chemical disinfection is only necessary to meet the residual requirements of the distribution system and to achieve virus inactivation. As with other microporous membrane filters, system performance can be routinely monitored by a pressure or "Membrane Test" to assure system integrity. Large scale water production, using microfiltration systems, is now possible with the use of innovative backwash and operating regimes in combination with efficient modular designs. These systems can be cost competitive with conventional technologies while offering the intrinsic qualitative advantages of microporous membrane filtration.