Steps taken during the last two decades have reduced exposures to lead in tap water. These steps include actions taken under requirements of the 1986 and 1996 amendments to the Safe Drinking Water Actexternal icon and the U.S. Environmental Protection Agency’s (EPA’s) Lead and Copper Ruleexternal icon. Even so, lead in water can come from homes with lead service lines that connect the home to the main water line. Homes without lead service lines may still have brass or chrome-plated brass faucets, galvanized iron pipes or other plumbing soldered with lead. Some drinking water fountains with lead-lined tanks and other plumbing fixtures not intended for drinking water (e.g., lab faucets, hoses, spigots, hand washing sinks) may also have lead in the water.
Lead can enter drinking water when a chemical reaction occurs in plumbing materials that contain lead. This is known as corrosion – dissolving or wearing away of metal from the pipes and fixtures. This reaction is more severe when water has high acidity or low mineral content. How much lead enters the water is related to:
- the acidity or alkalinity of the water,
- the types and amounts of minerals in the water,
- the amount of lead that water comes into contact with,
- the water temperature,
- the amount of wear in the pipes,
- how long the water stays in pipes, and
- the presence of protective scales or coatings in the pipes.
Source: Center for Disease Control and Prevention