What is mineral water?

Back to all articles 27 november 2016

The term ‘mineral water’ refers to natural water that originates from an underground source and rises to the surface via a spring or a well. It often has beneficial health properties. The source is highly dependent on the water cycle, which consists of two stages.

During the first stage, rainwater penetrates the soil (this is known as the saturation stage). Rainwater or melting snow seeps down through the porous ground, forming fissures and dips in the subsoil. During the second stage, the water filters through into the reservoir rock (the horizon stratum).

Horizon strata come in different varieties but generally speaking there are two broad categories:

  1. groundwater aquifers, where water flows freely through a saturated subsoil layer
  2. artesian strata, where the water is under pressure due to the special conditions found between two impermeable layers. Think of it like a high-pressure pipeline that conveys water from a hydroelectric power station dam to water turbines

As the water moves through or remains static in the soil, its physical and chemical attributes change. It is these changes which determine its composition.

First and foremost, the water absorbs dissolved minerals from the rock, altering its temperature and the quantity of dissolved gases it contains. The composition of salts depends primarily on the chemical influence of the ‘mother rock’, the key factor determining the properties of all types of mineral water. In terms of general mineral content, mineral waters can be classified as follows:

  • very low mineral content (total dissolved solids – up to 50 mg/l)
  • low mineral content (total dissolved solids – up to 500 mg/l)
  • high mineral content (total dissolved solids – more than 500 mg/l)

Water in the first category is often found in mountainous regions where the water seeps into the ground fairly quickly (in a year or more). The fast penetration of the water through the stratum is often related to the low solubility of the rock (metamorphic or volcanic rock, rich in minerals with low solubility such as quartz). As a result, this water has an extremely low mineral content.

On the other side of the scale is water that has undertaken a much longer journey underground, staying within the same stratum for decades. Such water is often characterized by its unusual temperature at the surface outlet, proving that it originates from much deeper underground strata. It contains higher concentrations of salts, a consequence of volcanic activity or the dissolution of highly soluble minerals, such as evaporite deposits (calcium, potassium salts, etc.).

There are many ways to recover mineral water, depending on the type of stratum to be opened up. Water from natural sources is recovered using simple water collection systems. The most common water collection systems include water reservoirs (reservoir wells), collecting drains, trenches and substratum wells, bored near the surface outlet of the water. This method makes it possible to increase the flow and better protect the source of the water at the same time. In other cases, mineral water lies deep underground and wells are bored to allow the water to rise to the surface.

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