Water is an important resource worldwide today. Although nearly two-thirds of the Earth is covered by water, drinking and irrigation water are still lacking in many parts of the world and are often wasted due to inefficient irrigation methods. This paper describes existing and emerging technologies that conserve water in agriculture, as well as technologies that desalinate seawater and ocean water as potential sustainable solutions for addressing the acute water scarcity that the world is facing today and will continue to face in the future.