This research was undertaken to see the technical and economic feasibility of the dual water system using ultrafiltration membrane. For technical feasibility study, dual water production system including membrane was set up. And three samples of different waste water sources, residential waste water, commercial waste water), and official waste water were collected and purified by the dual water production system. The experimental analysis showed that the all permeates purified through UF membrance satisfied the standards for Korean dual water regulation. For economic feasibility study, the mathematical form of cost model was developed and the cost simulation which can evaluate the cost and do the economic feasibility study was programmed. Economic feasibility was represented in terms of pay-back period. Technical and economical feasibility study showed that the dual water production system including ultrafiltration was turned out to be a promising process.