In 2010, King County was awarded a Puget Sound Action Agenda: Technical Investigations and Implementation Assistance Grant by the U.S. EPA to estimate loading of PCBs and PBDEs to Lake Washington, Lake Union and Puget Sound; and model potential reduction in Lake Washington fish tissue concentrations associated with select PCB loading reduction scenarios. A fate model was developed based on a simple two compartment (lake water and active sediment layer) model used to evaluate PCB fate in Lake Ontario and San Francisco Bay. An estimate of total PCB loading to Lake Washington based on field data collected as part of this study and model input values based on data specific to Lake Washington (when available) were used to test the model against observed water and sediment concentrations. Model sensitivity and uncertainty analyses were also conducted to identify critical model parameters and better understand the range in uncertainty in predicted water and sediment total PCB concentrations. The fate model was coupled to a food web bioaccumulation model, which is the subject of another conference presentation.