Abstract: A point-of-use membrane filtration system and method for water or other liquids including an automatic control system for purge, rinse-up, sanitization, or combinations thereof. The system may be used for microfiltration, ultrafiltration or hyperfiltration (reverse osmosis) depending on the membrane pore size of the filtration cartridge employed in the system. A reject valve at the bottom of the filter cartridge is automatically opened when filtered product is drawn, thus to direct some water and any waste to drain. The control system is programmed to accomplish purge, rinse-up and sanitization procedures at predetermined intervals with predetermined combinations of procedures.