The Lead and Copper rule, or LCR, regulates the control and monitoring of lead in drinking water. Revisions to the rule, finalized by the U.S. Environmental Protection Agency in 2021, dramatically slow down the rate at which lead pipes are required to be replaced. The new rule also allows small public water systems required to replace lead service lines to avoid replacing them altogether, even if those systems continually exceed the lead action level.

Most of the lead found in drinking water comes from lead service lines, according to the EPA. Lead service lines naturally corrode when water flows through them.

EPA estimates there are as many as 10 million lead service lines in the country, and researchers estimate lead pipes serve as many as 22 million people. Communities of color are disproportionately affected. A study by the Centers for Disease Control and Prevention found that 11.2% of African-American children and 4% of Mexican-American children are poisoned by lead.