Climate change poses a significant threat to the world's water resources since it alters the quantity, quality, and distribution of freshwater in various locations. This chapter examines the complex interactions between climate change and water systems. It also discusses the major issues and how to adapt for long-term water resource management. The rapid rate of global warming has altered how water moves through the environment, increased the quantity of rain that falls, exacerbated droughts and floods, and caused glaciers to melt and sea levels to rise. These consequences disproportionately affect disadvantaged groups and key sectors including agriculture, energy, and public health, particularly in low- and middle-income nations. Some of the most important topics of concern are how climate change affects surface and groundwater systems, how vulnerable water-dependent industries are, and how diminishing water security affects the economy and society. The report also discusses technological and policy solutions, such as integrated water resource management (IWRM), climate-ready infrastructure, water-saving technologies, and community-based adaptations. The chapter provides carefully chosen case studies to show how to employ effective implementation models and stresses how important it is to adopt inclusive, multi-stakeholder adaptation strategies. It also points up problems that are still there, like not having enough money, poor institutional frameworks, and not having enough climate-water data. Last but not least, it's important to invest in adaptation measures, capacity building, and international cooperation ahead of time to conserve water resources in a changing climate. Making water systems more resilient to climate change is important for the environment and for long-term social and economic security.