Today The Story begins a week-long exploration of water. We start by checking in with Charles Fishman, author of The Big Thirst. Also, when you think of Las Vegas, you might assume that making a city green in a desert would be a tale of colossal waste. There may be some truth to that, but Pat Mulroy will surprise you. She manages the city's water, and she's had a lot of success getting people to pull out their grass and dramatically cut back on water use.

Our series continues today with a look at technology. Charles Fishman, author of The Big Thirst, has seen plenty of water filters that fail and he talks about the "people factor." Physicist Ashok Gadgil grew up in India where several of his baby cousins died from bad drinking water. He came up with a kind of filter that's cheap and easy to repair, and he's hopeful about the success. It means millions of people now have clean water to drink.

Ned Breslin has spent twenty years trying to bring clean water to people in the developing world. While many people who do that kind of work tout their successes, Ned likes to talk about his failures. He says each one has taught him a little more about the magnitude of the challenges, and what it will take to make a difference. Photo: Ned's picture of Dona Fatima, the woman he met in Mozambique.