EDUCATIONAL TIP - Why Is The Ocean Salty? The ocean was not always salty. Rain falls on rocks and carries tiny bits of salt from the rocks into rivers. Rivers carry that salt into the sea. When water evaporates from the sea to form clouds, the salt stays behind. It doesn't go up with the water. So for millions of years, salt has been entering the sea but not leaving it. That is why the sea keeps getting saltier. One teaspoon of seawater has more salt than you think. #chineduruby