The Water Framework Directive (WFD) 2000/60/EC, requires a coordinated approach to water management in respect of whole river basins with a view to protecting the high-status of waters where it exists, preventing any deterioration in the existing status of waters and achieving at least "good status" in relation to all waters. The EPA-funded Monitoring Criteria for Priority Chemicals Leading to Emission Factors aims to establish risk factors for priority substances (PS) & priority hazardous substances (PHS), which will assist in defining the monitoring programme in Ireland for WFD. Indicators are applied to monitored WWTP agglomerations to predict the relative risk of elevated PS/PHS loading to receiving waters across agglomerations over time. In Ireland, where the current state of knowledge and data availability (e.g. emission data from individual installations) is insufficient to support high resolution based models the project team have developed a simple, stochastic, risk-based model that can be applied across catchments to predict the relative risk of elevated PS/PHS loading to receiving waters