Desalination is a term commonly used for removing salt from seawater, but it is essentially the process of Reverse Osmosis applied to very salty or seawater. Because the salt concentration of seawater is so much higher than brackish water the pressure required to overcome the osmotic pressure of the membrane is also so much higher.

Although desalination requires a lot of energy, it is still the most practical and effective way and thus the most widely used technology for removing salt from seawater.