This working paper compares two methods to estimate wastewater investment needs in EU member states. Estimates are useful for policy makers and regulators, to compare alignment with financing capacities and to consider policy options to bridge the gap or inform planning and financing decisions. This paper compares the method used by the OECD in 2020 when projecting investment requirements and financing needs for water supply, sanitation and flood protection across the EU28, with an agglomeration-based model for urban wastewater infrastructure only. Key differences are highlighted. Comparisons are made across methods for Articles 3, 4 and 5 of the Urban Wastewater Treatment Directive. The results are relevant for research and future projections and reviews of financing needs and capabilities.
