page_title: Lead service line
section_title: Internal corrosion control
hierarchical_section_title: Lead service line / Mitigation / Internal corrosion control
caption_attribution_description: English: Pumps used to add required amount of chemicals to the clear water at the water purification plant before the distribution. From left to right: sodium hypochlorite for disinfection, zinc orthophosphate as a corrosion inhibitor, sodium hydroxide for pH adjustment, and fluoride for tooth decay prevention.
context_page_description: A lead service line is a pipe made of lead which is used in potable water distribution to connect a water main to a user's premise.
  Lead exposure is a public health hazard as it causes developmental effects in fetuses, infants, and young children. It also has other health effects in adults. According to World Health Organization, the presence of lead service lines is the most significant contributor of lead contamination in drinking water in many countries.
  The most certain way to eliminate lead exposure in drinking water from the lead service lines is to replace them with pipes made from other materials. However, the replacements are time-consuming and costly. The difficulty is exacerbated in many locations by ownership structure that has a shared responsibility between water utilities and property owners, which requires cooperation between the two entities. Some water utilities employed corrosion control as a short-term solution while working through the long-term replacement projects. A potential issue with corrosion control is a constant monitoring of its effectiveness.
context_section_description: Various techniques can be used by water utilities to control internal corrosions, for example, pH level adjustment, adjustment of carbonate and calcium to create calcium carbonate as piping surface coating, and applying a corrosion inhibitor. An example of corrosion inhibitor is using phosphate products such as orthophosphate to form films over pipes. This reduces the chance of leaching of trace metal including lead from the pipe materials into the water. Another example of corrosion inhibitor is to use silicate products. However, the mechanism of film forming and its effectiveness are not well understood.
caption: Corrosion inhibitor added by a pump at a water purification plant
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