What would you do if you turned on the faucet one day and nothing happened? What if you learned the water in your home was harmful to drink? Water is essential for life on this planet, but not every community has the safe, clean water it needs. In When the World Runs Dry, award-winning science writer Nancy Castaldo takes readers from Flint, Michigan, and Newark, New Jersey, to Iran and Cape Town, South Africa, to explore the various ways in which water around the world is in danger, why we must act now, and why you’re never too young to make a difference.