In the preamble of the Department of Health of South Africa (2006) regulations that can be viewed at www.doh.gov.za/department/dir_foodcontr.html are the following definitions for “Natural Water”.

"natural mineral water" means bottled natural water which contains mineral salts in various proportions and which is characterised by the presence of trace elements and other substances such as calcium, magnesium, sodium, and potassium;
"natural water" means bottled water derived from an underground formation which has not been modified and has not undergone treatment
"spring water" means bottled water sourced from an underground formation from which water flows naturally to the surface of the earth, and which is collected from the spring or a borehole tapping the underground formation, and which may be classified as a 'natural water' or as ‘water defined by origin’
Dept of Health of South Africa. 2006. Regulations relating to all bottled waters. Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act no. 54 of 1972) No. R. 718. 28 July 2006

The unifying thread for this class of bottled water is that this water has flowed through rock strata and has acquired the mineral characteristic of those strata. As the water flows through these strata the water slowly dissolves the minerals that makes up the rock, and it is these dissolved minerals that gives the bottled water its chemical and trace mineral character.

The second important aspect is the term “natural”. All water, whether from a spring, a river, the sea, or a municipal tap has a mineral content. The important aspect of this class of water is that both the natural mineral and the natural microbiological content may not be altered by any method. The only allowable treatment is the removal of coarse particles such as sand grains, and removal of unstable components such as iron oxides.

Now, although water from a mountain stream is “natural” such a water cannot be classed in this category, as, in order to make water from a mountain stream safe for consumption, it is necessary to sterilize this water. By sterilizing this water the second of the above requirements is transgressed and thus, under South Africa’s bottled water regulations, the water cannot be called a natural water.

One of the defining characteristics of a natural water is the constancy of its mineral content under natural conditions. Boreholes that are sampled regularly over periods of decades seldom show any significant variation of chemical composition. Only when the boreholes are subjected to human activities such as overpumping or contamination does one sometimes find significant changes of chemistry. Thus a properly managed and protected source of natural mineral water will give a water with a stable and balanced mineral content for many decades.

Note that spring water under the Dept of Health Regulations can be classified as either “Natural Mineral Water” or as “Water defined by Origin”. If it is not sterilised it can be classed as “Natural Mineral Water”, but if the bottler decides that the water, for the consumer’s safety, must be sterilized, then it is classified as “Water defined by Origin”.

Natural water may not be transported in bulk from the source to another facility where it is bottled.

Labelling
The following is required to be indicated on the label:

The name of the product: “natural mineral water” or “natural spring water”
The name of the source and the physical address of the source
The analytical composition in milligrams per litre in the same order as provided in the regulation.
Descriptors as “still” or “non-carbonated” and “sparkling” or “carbonated”