The aim of this document is to provide guidance on designing appropriate and cost-effective forests for water payment schemes that support tree planting and forest management to protect and improve water quality. The PESFOR-W COST Action has published this detailed user manual as one of the main outputs of the project. The guide is structured by the main steps involved in establishing a payment scheme, starting with identifying the water issues and how tree planting and forest management can help, managing potential disbenefits, exploring multiple benefits, followed by scheme design, monitoring and communication. It is applicable to all actors involved in sustainable water management, farming and forestry, from policy makers, catchment planners and land managers, to private investors, practitioners and local communities. Applying this guidance will provide a common language and framework to help ensure schemes are successful in delivering water and other ecosystem services, while minimising possible trade-offs (such as the potential for tree planting to reduce water resources).