The importance of water quality data needs not to be overemphasized. The effort to ensure clear and correct data is the most important task in water quality field. The main objective of this project is to evaluate and validate the water quality data monitored by three independent firms for Taiwan’s three watersheds. Additionally, the team is charged to prepare the annual water quality report and, to some extent, to assist Taiwan EPA’s upgrading and maintenance of the web site for water bodies and water quality in Taiwan (http://www.epa.gov.tw/monitoring/pa21.htm). The key objective in evaluating water quality data is to identify the abnormal data as well as to verify the accuracy of the data. One needs to know whether the abnormal data should be discarded or they truly represent the actual conditions. Standard operating procedures have been prepared to achieve this goal. The major task is to ensure that strict QA/QC procedures and protocols are followed by monitoring companies for their water quality data with respect to their planning, sampling, testing, calculation, and reporting. All monthly and seasonal data that meet the above criteria are used for subsequent seasonal report and then incorporated into the data bank for eventual public dissemination. The annual water quality report, in reference of 1996 Water Quality Report as well as those reports of developed countries, emphasizes the extent of water quality that fail to meet the regulatory standards. The spatial and temporal data distribution serves not only public interest, but also as a tool for water quality pollution control strategy. The annual report (551 pp) includes the four major water bodies: streams, reservoirs, groundwater, and coastal areas. The validated monthly data from three watersheds are transformed to electronic files to facilitate the entry into the web site. For site upgrading including user friendly and expanding the content, the additional features incorporated include