Net Zero Strategy: Build Back Greener Resources and Waste: For municipal wastewater, water companies use the Carbon Accounting Workbook developed by UK Water Industry Research to estimate operational GHG emissions across the industry. The workbook has been in place since 2004 and is updated annually to reflect the needs of the industry, including changes in carbon accounting practices with updated emission factors to align with the latest UK and international data. There are no internal models for private or industrial emissions and there are still significant gaps in our understanding of the magnitude and main sources of these. The Water UK Routemap to 2030 sets out industry plans to achieve net zero by 2030.113 This routemap has been used as the basis for Defra to develop net zero consistent policies, for example, using assumptions from industry on cost and feasibility of policy deployment. For landfill emissions estimation, the Landfill Environmental and Financial (LEAF) model has been used. This was developed by Resource and Waste Solutions, and more detail can be found in their report.114 This is a high-level and strategic model of non-hazardous waste flows in England. LEAF allows the different scenarios to be described numerically and their effects on landfill emissions and costs of landfill to be calculated. The model considers the impacts of changes on landfill gas, leachate and void space consumption. The model is England only, but to provide an indication of Devolved Administration potential, emission savings are scaled to a UK level using relative emissions shares between England and the Devolved Administrations. It is assumed that there is a linear increase in diversion from landfill after 2021.