Natural mineral water is clearly distinguishable from drinking water by its nature, featuring a mineral content, and by its purity, which makes it fit for human consumption in its original state.

Directive 80/777/EEC on the exploitation and sale of natural mineral water stipulates that this water, as it springs from the ground, can only be subjected to certain treatments, establishing that the safety of treatments other that filtering or decanting (preceded by oxygenation, if necessary), must be assessed by the European Food Safety Authority (EFSA), and its conditions of use have to be approved at EU level by the European Commission.

Only natural mineral water complying with the maximum limits laid down in Directive 2003/40/EC for 15 undesirable constituents in natural mineral water can be sold in the EU. Among the constituents are manganese (0.5 mg/l) and arsenic (0.01 mg/l). Those that do not comply must be removed from the market or treated with permitted treatments. The reduction in the iron content is permitted due to technical reasons.

EFSA has published on it web page a scientific opinion on safety in the use of treatments to eliminate manganese, iron and arsenic from natural mineral water via oxyhydroxides, drawn up by the organisation's Panel on Additives, Flavourings, Technological Processing Aids and Materials in Contact (AFC). The conclusion of this opinion is that it is proven that the use of mediums based on oxyhydroxides of iron and manganese is suitable for selective elimination of iron, manganese and arsenic from natural mineral water. These elements are eliminated by a physical treatment known as adsorption. Under optimal condition, the release of cations and anions from the mediums is negligible and does not pose a risk to public health. Therefore, the process complies with the basic requirements of Community directives.