All drinking water, including tap water and water that is called "mineral water" basically includes the same salts in compositions and concentrations that depend on the environment where the water flows. Water is the "universal solvent" and carries different minerals washed away from the rocks with which it comes into contact in its natural environment, and this is the factor that determines its natural quality. About two-thirds of the planet is covered in water, which is called the "hydrosphere" and describes the combined mass of water found on, under and over the earth's surface. The hydrosphere is one of the four spheres around the earth.Of all the componentsof the hydrosphere, the water that is fit for human use is surface water (on the surface of the continents) and groundwater (water that has seeped down from the surface and is the source of water in springs and wells). In Israel, a random test of mineral concentrations in the wells subject to the Ministry of Health's supervision and their comparison with the mineral concentrations in "mineral" water indicates that the concentrations are similar, and that both kinds of water provide a tiny amount of the quantity the body requires compared to the amount of minerals we get from our food.