Improved management of water and sanitation services is fundamental not only for climate change adaptation but also for mitigation – and collaboration plays a major role in this. This report describes important guidelines as well as specific approaches and regulatory framework conditions for cross-sectoral collaboration in country case studies from around the world. It shows that low-carbon and climate-resilient water and sanitation services are technically feasible and economically viable, and that cross-sectoral collaboration and climate adaptation regulatory framework can add important value for the implementation of SDGs and the Paris Agreement.