Here are some common terms relating to mineral and spring waters.
An aquifer is a underground layer of gravel or permeable rock, that stores a large amount of water. The water comes to the surface through a spring or a well.
Artesian water comes from a confined aquifer that has no porthole to the surface of the earth. When the aquifer is tapped, the pressure forces the water up to the surface without the need for pumping.
Carbonation refers to the level of carbon dioxide (CO2) in the water. CO2 is the gas responsible for the ‘sparkle’ in sparkling waters. It may occur naturally and be found in the bottle at the same level as its source (as with Badoit and Gerolsteiner), it may occur naturally but be captured and later reintroduced into the bottle (as with Perrier), or it may be added artificially to give a naturally still water sparkle (all NZ waters).
Naturally occurring sparkling mineral waters are highly prized as carbonation may enable waters to absorb more minerals. Natural carbonation is also often associated with nearby volcanic activity. The addition of CO2 also increases the acidity of the water, due to the reaction between CO2 and H2O producing H2CO3 or carbonic acid.
Groundwater is water from below the ground, usually sourced from aquifers. Mineral and spring waters are derived from groundwater. Whereas surface water is water from above the ground (e.g. lakes, rivers).
Hard water has a higher mineral content than soft water. A water’s ‘hardness’ is usually calculated by adding the Calcium and Magnesium levels together. The exact formula is:
HARDNESS = (CALCIUM * 2.5) + (MAGNESIUM * 4)
Hard water is not bad – it just indicates a higher level of Calcium and Magnesium. The reason municipal water suppliers ‘soften’ water is because hard tap water makes cleaning more difficult (it doesn’t ‘lather’ as well as soft water) and because of scale build up (Calcium Carbonate). Boiling hard water causes precipitation of minerals which forms as limescale deposits in your kettle.
PET stands for polyethylene terephthalate, and is the type of recyclable plastic commonly used to bottle water. It is lightweight and shatter resistant, and has been extensively tested for safety. It is BPA free.
pH indicates a water’s level of acidity or alkalinity. It is measured on a scale of 1 to 14. On this scale 1.0 to 6.9 is acidic, 7.0 is neutral, and 7.1 to 14.0 is alkaline. Bottled water usually ranges from 5-10. Our body’s blood natural pH is in the range 7.35 to 7.45, and pH varies throughout the body.
Only water sourced from underground, water-bearing strata (as defined in the Australia New Zealand Food Standards Code) with natural minerals may be labeled as natural mineral or spring water. No minerals may be added to the water.
Surface water is water from above the ground (e.g. lakes, rivers). Whereas groundwater is water from below the ground, usually sourced from aquifers. Mineral and spring waters are derived from groundwater.
TDS (total dissolved solids) indicates the amount of dissolved minerals in one litre of water, measured in mg/L or parts per million (ppm) which are equal.
Regulations regarding TDS vary throughout the world. In Australasia only natural water with a TDS of over 250 mg/L can be called “mineral” water. Water with a TDS of less than 250 mg/L is usually labeled as natural “spring” water.