Lead service lines were banned from new plumbing systems in the US in 1986, but plenty of the nation's old pipes still remain. Today, nearly a third of US water systems are known to contain lead service lines. When the pipes corrode, they can release toxic lead into local drinking water, posing a danger to residents' health.
Children exposed to lead can suffer permanent brain damage, which often results in learning disabilities and increased violent behavior. In adults, chronic exposure to low levels of lead can cause nausea, seizures, and reproductive issues.
In addition to Flint, Michigan, cities like Detroit, Pittsburgh, and Washington, DC, have all seen unsafe levels of lead in their water supplies in the recent past.