AbstractWorldwide, 1.2 billion people lack access to sufficient amounts of clean water, and 2.6 billion lack adequate sanitation. Also, industry relies on large quantities of water during manufacturing, which is then returned to the environment. Having adequate water supplies, and removing pathogens, chemicals, and other contaminants with high throughput at a low cost is a growing challenge around the world. This issue of MRS Bulletin examines how materials research, through the development of membranes, catalysts, nanoparticles, and other materials, is addressing these needs.