Causes of corrosion vary but are commonly attributed to primary and secondary water characteristics, physical water characteristics and bacteria. Other factors besides water characteristics and bacteria can cause corrosion too. Quality and age of metal pipes and the presence of electrical currents are other influential factors that may expedite corrosion.
In addition to having multiple sources, corrosion usually comes from several culminating factors. Poor water quality, for instance, may lead to the growth of bacteria, which helps to accelerate the rate of existing corrosion. Primary water characteristics are among the greatest factors in determining the extent and rate of corrosion. These traits include water hardness, alkalinity, pH balance, dissolved solids and the volume of carbon dioxide present in the surrounding pipe.
Secondary water characteristics, which include scaling, chemical composition and oxygen, may also trigger corrosion. Physical characteristics of water include temperature and velocity of water flow; these traits may also facilitate corrosion. High water temperatures cause metals to wear more quickly, and invite the growth of bacteria, which also play contributing roles in the spread of corrosion. High-flow velocity may remove protective scales and tubercles and increases the contact of oxygen with the pipe, which exacerbates corrosion rate. Lastly, bacterial colonies may cause and accelerate the rate of corrosion as well.