In response to increased interest and policies regarding source water protection issues, Mohawk Valley Water (MVW) developed a comprehensive source water assessment protocol with the intention of establishing a long-term database documenting the quality of raw source waters entering its reservoir. Hinckley Reservoir is a state-owned, man-made, multi-use reservoir created in the early 1900s and is MVW's sole source of drinking water for over 125,000 people. The 7-mile long, 25 billion gallon reservoir and its associated watershed area, (374 square miles), are located in the southeastern portion of the Adirondack Park in New York State. Mohawk Valley Water developed and implemented a primary source water assessment plan in 1997 as a means to establish information-sharing cooperatives among the various levels of governments, citizen groups and other parties interested in Hinckley's environmental state. The plan was magnified when MVW was awarded an EPA grant entitled "Source Water Protection for a Large Rural Watershed." Beginning in January 2000, the comprehensive project analyzed water quality conditions and changes through qualitative and/or quantitative biological, chemical, microbiological and planktonic indicators. Sampling occurred weekly through two sampling seasons from eight tributaries that were representative of different sub-watersheds of Hinckley. Further analyses incorporated into the study were geographic information system (GIS) mapping strategies and land- use data acquisition. This was fulfilled with the addition of a Watershed Coordinator/GIS Specialist to the MVW team to aid in the establishment of correlations between water quality issues and related watershed activities. Results indicate that the greatest potential problems for drinking water remain with the reservoir itself. Due to its multiple uses (supplement NYS Barge Canal water levels, hydroelectric power generation, drinking source water, recreational day-use picnic/swim area and watercraft activities) and with a number of camps and year-round dwellings around the reservoir, improper management may upset the balance in the water, negatively affecting water quality, thus increasing treatment costs. Elevated TOC concentrations in the raw water are observed regularly, but the current treatment process greatly reduces the levels in finished water. Continued monitoring is imperative and has been carried out on a monthly basis since the initial study period. Additional work incorporated into the plan since the grant completion include macroinvertebrate species diversity analyses in the sub-watersheds, the implementation of a plan to identify failing septic systems within 1000 feet of the reservoir, and depth-integrated sampling in the reservoir at the depths of the two raw water intakes. Additionally, Mohawk Valley Water successfully lobbied the US Geological Survey to install a gauging station on the West Canada Creek, the largest tributary to the reservoir. In continuing to foster public participation, stakeholder meetings are being sponsored by MVW to keep members apprised of new developments and to build upon newly created support networks. Collaboration among the various parties and letters of support for individual grant initiatives has greatly benefited member groups. Finally, interpreting collected data and establishing relationships between water quality and watershed activities will serve to guide future management and treatment practices. Includes 7 references.