Basic Information
EPA’s Research Helps to Control Corrosion and Reduce Release of Metals into Our Drinking Water Distribution Systems (DWDS) Corrosion and the Cost of Maintaining and Replacing DWDS Infrastructure Corrosion—a big problem for our drinking water distribution systems—is caused by oxidation or chemical action. EPA has estimated that $138 billion will be needed over the next 20 years to maintain and replace existing drinking water systems and that $77 billion of this will be dedicated to repairing and rehabilitating pipelines. Many water distribution systems in the United States are approaching 100 years in age, with an estimated 26 percent of distribution system pipeline being unlined cast iron and steel that is in poor condition. Corrosion, Water Quality, and Public Health Corrosion by-products that form on the surface of pipes and fixtures affect the solubility of lead, copper, and iron, and ultimately their levels at the consumer’s tap. Other types of scales (hard mineral coatings) can form diffusion barriers on metal pipe surfaces, which can reduce the release of metal into water distribution systems. In addition, corrosion by-products and other solids that accumulate in a distribution system can adsorb trace contaminants, such as arsenic, thus removing them from the free-flowing water in distribution system pipes. However, the contaminants are then subject to potential release back into the water when system conditions change due to water demand, temperature, treatment changes, and other factors. The release of trace contaminants that have adsorbed over time could cause elevated levels at the consumer’s tap; therefore, these contaminants are a focus of the corrosion research conducted at the EPA. Technical Contact:Darren Lytle (513) 569-7432 See Also:About Drinking Water Distribution Systems
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