Why can we not use ocean water?

Seawater is toxic because your body fails eventually when it has to try to get rid of the salt that comes from sea water. Your body normally gets rid of excess salt by having the kidneys produce urine, but it needs freshwater to dilute the salt in your body for the kidneys to work properly. read more

Even with all of the water in Earth's oceans, we satisfy less than half a percent of human water needs with desalinated water.* We currently use on the order of 960 cubic miles (4,000 cubic kilometers) of freshwater a year, and overall there's enough water to go around. There is increasing regional scarcity, though. read more

In most coastal communities, seawater is not used for domestic purposes because: (1) significant infrastructure (pipes, pumps and so on) would need to be installed (2) seawater is more corrosive on pipes and fittings (3) toilets represent a small fraction of water use. It is used in Kong Kong, where about 75% or apartments use salt water for toilets. read more