Five years of drought have brought both big challenges and big changes to California’s urban water systems. Amid yearlong mandatory water cuts, residents of California’s cities have made massive efforts to conserve water at home and at work. Many water agencies have stepped up programs to treat and reuse water. Policymakers have made headway in regulations for water recycling. But there’s ample room for growth. Experts around the world are watching how Californian cities think, research and innovate to create a path of sustainable growth in a future with fewer water resources.