Today, one out of three people don't have access to safe drinking water. One reason is that 96.5% of that water is found in our oceans. It's saturated with salt, and undrinkable. Most of the freshwater is locked away in glaciers or deep underground. Less than 1% of it is available to us. So why can't we just take all that seawater, filter out the salt, and have a nearly unlimited supply of drinkable water? Desalination plants are trying to fix that.