When is water safe to drink?

Water...it's a basic human need, but what happens when you don't have clean water? And more importantly, how do you know when it's safe to drink?

"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."