While early EPA bans on leaded gasoline and lead paint dramatically reduced the burden of lead poisoning in the nation, old lead water service lines can leach the toxic metal into the water supply, creating a particular danger to young children.

The EPA estimates that 400,000 schools and ten million homes rely on lead service lines for their water delivery.

"The science on lead is settled—there is no safe level of exposure and it is time to remove this risk to support thriving people and vibrant communities," said EPA administrator Michael Regan in a statement, who hopes to pair the removal project with regulation that will see lead pipes forever beyond the reach of pipelayers and housing manufacturers.