This study examined the reuse potential of the effluents discharged from several unified wastewater treatment plants (WWTPs) of industrial parks in Taiwan, with designed capacity exceeding 10,000 CMD. Parameters were selected based on the relevant reuse purposes. The "potential recycling percentage", R of the WWTP effluent was defined as the maximal percentage of pure water extractable by the "ideal reverse osmosis module" while the RO retentate still met local effluent standards and required no treatment. The analytical results demonstrated that the WWTP effluents had potential for recycling. A pilot plant was installed in one of the WWTPs. The treatment process included a sand filter, an ultrafiltration unit (UF) and a reverse osmosis module (RO). Results of this study demonstrated that the production quantity and quality are stable and appropriate for various purposes, including both industrial and domestic applications.