The Safe Drinking Water Act requires the EPA to determine the level of contaminants in drinking water that does not cause adverse health effects with an adequate margin of safety. These health-based goals, which are not enforceable and are based solely on potential health risks, are known as Maximum Contaminant Level Goals (MCLGs). The EPA has determined that the Maximum Contaminant Level Goal for lead in drinking water is zero because lead is a toxic metal that can harm human health, even at low levels of exposure. Lead is persistent and can bioaccumulate in the body over time.
Children, babies, and fetuses are the most vulnerable to lead, as the physical and behavioral effects of lead occur at lower levels of exposure in children compared to adults. A dose of lead that would have little effect on an adult can have a significant impact on a child. In children, even low levels of exposure have been linked to damage to the central and peripheral nervous systems, learning and growth problems, hearing impairment, and issues with the formation and function of red blood cells.
