'Killers' part 2 - Keeping water flowing with smartphones

Water is essential for life. So when your only source of safe water is from a water pump you grow to depend on it. If it broke then you'd have to walk further, or go thirsty. With so many water pumps so vital to so many vulnerable communities in developing countries Dr David Clifton explains how the work they're doing seeks to find a way of monitoring large numbers of water pumps, using smartphones. And with the huge volumes of data collected, can they spot patterns that give tell-tale signals that other things aren't going right in the community?