Clean Water Services in Washington County Oregon was issued a watershed–based National Pollutant Discharge Elimination System permit by the Department of Environmental Quality. This permit allows a watershed wide approach to managing water quality in the Tualatin River watershed. GIS is being used to link watershed-scale planning, permitting, project implementation and evaluation, and adaptive management through monitoring. Using GIS techniques scientist and managers are able to efficiently establish and prioritize water quality projects. High quality GIS data can be applied to multiple water quality management projects therefore reducing data collection and processing cost.