A geological formation that stores large amounts of water which may come to the surface through a spring or a well.  Most are made of sand, gravel, or permeable rock and are surrounded by clay or another impervious substance.  More than one aquifer may exist a various depths in the same location, separated by impermeable layers.



Artesian aquifers are surrounded by impermeable rock which puts the water under pressure.  When the aquifer is tapped, the pressure forces the water up the well without the use of any mechanical aids.



A water's calcium and magnesium levels add together to determine the water's hardness.  Hard tap water (containing a high level of calcium and magnesium) makes cleaning more difficult and causes scaling in tea kettles and the like.  Water is softened by ion exchange and the addition of sodium.


pH Factor

The pH (potential hydrogen) measures the level of alkalinity or acidity in water.  On this scale, 1.0 to 6.9 is acidic, 7.0 is neutral and 7.1 to 14.0 is alkaline (also referred to as basic).  Sour tastes (ie vinegar) come from acids, whereas alkaline substances tend to taste bitter.  In the 5 to 9 range, the pH factor plays a very minor role in the overall perception of water.


 Total Dissolved Solids (TDS) or Minerality

The amount of minerals dissolved in water is indicated as total dissolved solids, usually measured in milligrams per litre (mg/l).  Most waters fall in a TDS range of 50 to 2,000 mg/l.



Virginality indicates how protected a water is from its surroundings.  It is determined by the water's level of nitrate, an inorganic compound made up of one nitrogen atom and three oxygen atoms.  Nitrate is easily carried through soil by water.  In its natural state, water has less than 1mg/l of nitrate - higher levels typically reveal compromised water.