Why is the sea water salty?

Wherever water comes into contact with the rocks of Earth’s crust, either on land or in the ocean or within the oceanic crust, some of the minerals in the rock dissolve and are carried by the water to the ocean. The salt content of seawater does not change because new minerals are forming on the sea floor at the same rate as salt is added. Thus, the salt content of the sea is at steady state.