As of September 2008,45 Automatic Water Quality Monitoring Systems (AWQMS) have been installed at different sites on the 4 rivers to detect early the presence of pollutants in water and to issue an alarm. We count the number of issuing alarms by AWQMS, however, we will find the alarm has hardly been issued. The reasons for the scarcity of alarm issue are extensively being examined. The National Institute of Environmental Research attributes wrong alarm criteria for each AWQMS station to one the reasons. In this study, a suggestion has been made to modify the current alarm criteria to correspond with characteristics of river water quality. The current system with only two criteria (low and high) should be replaced as four-criteria systems (low, medium, high, and severe) based on cases of other advanced countries and stream conditions of Korea. The highest value of data collected for 5 years was suggested as the alarm criteria for each parameter. Meanwhile the alarm criteria for VOCs, phenol and heavy metals were established as same as drinking water quality criteria.