Water Data and Formulas

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Water Hardness

Water hardness is a function of the amount of dissolved calcium salts, magnesium salts, iron and aluminum.  The salts occur in a variety of forms but are typically calcium and magnesium bicarbonates (referred to as "temporary hardness") and sulphates and chlorides (referred to as "permanent hardness").

Although the most obvious effect of hard water is in preventing soap from lathering, most people cannot tolerate drinking water that exceeds 300 ppm carbonate, or 1500 ppm chloride, or 2000 ppm sulphate.

The following formula is used to calculate total hardness:

Ca = Calcium
Mg = Magnesium
Fe = Iron
Mn = Manganese


Hard water is treated by either a zeolite process (home water softeners) or a lime-soda ash process (large operations).