View full lesson: https://ed.ted.com/lessons/when-is-wa...

Water is refreshing, hydrating, and invaluable to your survival. But clean water remains a precious and often scarce commodity – there are nearly 800 million people who still don’t have regular access to it. Why is that? And how can you tell whether the water you have access to — whether from a tap or otherwise — is drinkable? Mia Nacamulli examines water contamination and treatment.

Lesson by Mia Nacamulli, directed by Rooftop Animation.