Freshwater : Fresh water is a water whose low salinity allows consumption. It is water from rivers, lakes, rain, glaciers, bogs, etc. as opposed tosea water. It is an essential criterion of drinkability because the water is very difficult to free from the salt in solution. Soft water generally contains less than one gram of dissolved solids (such as mineral salts, metals and elements nutritious) per liter. By way of comparison, sea water contains more than thirty and physiological saline contains 9 g / liter (0,9%).
In aquatics, the term "fresh water" is used to distinguish unsalted water from "sea water" and brackish water.
Note: Soft water is not the reverse of hard water which is defined as water containing magnesium and / or calcium ions. Thus, salt water (containing sodium chloride dissolved) is neither soft nor hard.
Fresh water is said to be renewable due to the water cycle. Fossil water therefore cannot be renewable.