OVERVIEW

Corrosion is one of the most important problems in the drinking water industry. It can affect public health, public acceptance of a water supply, and the cost of providing safe water. Deterioration of materials resulting from corrosion can necessitate huge yearly expenditures of resources for repairs, replacement, and system. Many times the problem is not given the attention it needs until expensive changes or repairs are required.

Corrosion tends to increase the concentrations of certain metals in tap water. Two potentially toxic metals (lead and cadmium) are attributable almost entirely to leaching caused by corrosion. Three other metals copper, iron, and zinc cause staining of fixtures, or metallic taste, or both. Low levels of tin and antimony can be caused by the corrosion of lead-free solders (Herrera, Ferguson, and Benjamin, 1982; Subramanian, Connor, and Meranger, 1991; Subramanian, Sastri, and Connor, 1994). Nickel has sometimes been mentioned as a potential contaminant from the plating of decorative plumbing fixtures. The promulgation of the Lead and Copper Rule by the U.S. Environmental Protection Agency (USEPA) in 1991 has created an emphasis on corrosion control in distribution systems, as well as domestic, public, and institutional plumbing systems ( Federal Register , 1991a,b, 1994a).

Corrosion products attached to pipe surfaces or accumulated as sediments in the distribution system can shield microorganisms from disinfectants (see Chapter 18). These organisms can reproduce and cause problems such as bad tastes, odors, slimes, and...