Around the world, cities, farmers, industries, energy suppliers, and ecosystems are increasingly competing for their daily water needs. Without proper water management, the costs of this situation can be high, not just financially, but also in terms of lost opportunities, compromised health and environmental damage. Without major policy changes and considerable improvements in water management, by 2050 the situation is likely to deteriorate, increasing uncertainty about water availability. This chapter summarises the key pressures on water, as well as the main policy responses. It starts by looking at current water challenges and trends and how they could affect the water outlook in 2050. It considers competing demands for water (from agriculture/irrigation, industry, electricity, domestic/urban supply, environment flows) and over-exploitation (both surface and groundwater), water stress, water-related disasters (e.g. floods), water pollution (in particular nutrient effluents - nitrogen and phosphorus - from agriculture and wastewater) and discharge into the seas, and lack of access to water supply and sanitation (as defined by the Millennium Development Goals or MDGs). It reviews the existing policy tools to manage water (such as water rights, water pricing), and explores how the water outlook could be improved by more ambitious policies. The chapter discusses emerging issues in water policy; it pays particular attention to water as a driver of green growth, the water-energy-food nexus, allocating water for healthy ecosystems, and alternative sources of water (reuse). For all these, governance, the use of economic instruments, investment and infrastructure development are important dimensions. They all contribute to and facilitate water policy reforms in OECD countries and globally.