The most common source of lead exposure is from paint in homes and buildings built before 1978. Lead-based paint and lead-contaminated dust are the main sources of exposure for lead in U.S. children. Lead-based paints were banned for use in housing in 1978.
Although the main sources of exposure to lead are ingesting paint chips and inhaling dust, lead also can be found in some household plumbing materials and some water service lines. The Environmental Protection Agency (EPA) estimates that 10 to 20% of human exposure to lead may come from lead in drinking water. Infants who consume mostly mixed formula can receive 40 to 60% of their exposure to lead from drinking water.