Can you live off of seawater?

Seawater is toxic to humans because your body is unable to get rid of the salt that comes from seawater. Your body’s kidneys normally remove excess salt by producing urine, but the body needs freshwater to dilute the salt in your body for the kidneys to work properly.

Why can’t we just use ocean water?

Even with all of the water in Earth’s oceans, we satisfy less than half a percent of human water needs with desalinated water. … The problem is that the desalination of water requires a lot of energy. Salt dissolves very easily in water, forming strong chemical bonds, and those bonds are difficult to break.