The World's Water-Smart Cities

National Geographic finds some of the smartest water cities in the world, from Tianjin to the slums of Uganda to Singapore.

"Singapore has become the poster child for urban water efficiency and innovative water recycling technologies, drawing investment dollars and talent from major corporations such as Siemens and GE, which are hoping to expand their water-recycling businesses in the growing cities of Asia. Singapore itself is investing $240 million over five years in water technology research.

The city-state's national water agency, PUB, employs a strategy it calls Singapore's Four National Taps to ensure an adequate supply of water for its five million residents and the economy, with the end goal of total water self-sufficiency."