Lead is a highly toxic metal that is harmful to all humans, but children under six are at special risk. Since their bodies are still developing, they can absorb lead into their systems easier than adults. There is no safe level of lead in the body but even low levels in a child’s system can slow down growth and impair learning.
Lead is a chemical element that is a heavy metal. Under normal conditions, lead will not react with water. Except in very low alkalinity waters, lead enters the water not so much from direct contact with the lead pipe wall as from contact with lead-rich corrosion products formed as a scale on the pipe wall. The overall solubility of lead in drinking water, is controlled by the solubility of these corrosion products and this in turn is strongly influenced by alkalinity and pH.
In 1991, EPA published the LCR to minimize lead and copper in drinking water. The rule replaced the previous standard of 50 ppb, measured at the entry point to the distribution system.
The rule established a maximum contaminant level goal (MCLG) of zero for lead in drinking water and a treatment technique to reduce corrosion of lead and copper within the distribution system.
For information on revisions to the LCR, visit EPA’s Lead and Copper Rule page.