Question

how is sea water made potable

Answer 1

Sea water is made pure by removing an excess NaCl from it. This could be done by boiling water and then condensing the pure water vapours separately in different container.

Generally it is done by reverse osmosis (RO) and ultra filtration technique.

RO is generally used for home filtration and purification of water

In RO Pressure is exerted on the side with concentrated solution to force the water molecules across the membrane to fresh water side.