The objective of this research was to develop online surveillance networks on the sewer pipe line coming from influent of industrial wastewater hookup to main line of the sewage treatment plants. The online surveillance networks was installed for detecting illegal discharges of the wastewater contamination sources from industrial factories through an ubiquitous network system. The ubiquitous network system has proven effective for appropriate maintenance, management, efficiency improvement and cost reduction of the sewage treatment facility. The ubiquitous system was consisted of two components which were an industrial pH meter (Model WSP-100, Korea) for measuring pH and a mobicon (Model MS-G401, Korea) for inputting and outputting measured pH data. When electric power problems occurred or lower pH were detected in the system, a letter transmission was immediately sent to a supervisor by a mobile phone for warning of losing of data or indicating illegal discharges of industrial wastewater in the area under investigation. The pH of sewage in K-1 and K-2 sampling sites was ranged from 2.6 ~ 8.3 (6.8) and 2.7 ~ 7.3 (6.9) respectively. Also, the most commonly detected heavy metals and anions were in the K-1 and K-2 sampling sites Cr, Zn, Fe and Cl-, SO42- respectively. As a result of the presence of metallic wastewater in influent from wastewater treatment facilities, the ubiquitous network system was the most effective tool to provide a very stable water quality. This pollution prevention system was clearly producing positive results.