AWWA JAW62339

The Lead and Copper Rule (LCR), which requires data on total metals concentrations and tries to establish the worst-case scenarios that can develop in a distribution system, has influenced the drinking water industry's perspective on corrosion issues even when the problems do not fall under the rule's jurisdiction. Utilities may use total metals concentrations to make decisions about corrosion in their systems, and as a result, select the wrong corrosion control approach. In some cases, the typical corrosion control strategies proposed in reference books and the LCR, alkalinity and pH adjustment, calcium hardness adjustment, and addition of a phosphate- or silicate-based corrosion inhibitor, are irrelevant to the problem at hand. The LCR, with its emphasis on health effects data collection, does not address the steps needed to assess water system factors that can contribute to corrosion. This article explains how differentiation of dissolved and particulate metals can be used in corrosion investigations to define the mechanisms involved in corrosion and select appropriate remediation strategies. Includes 23 references, table, figures.