The use of lead in plumbing was not federally prohibited in the U.S. until 1986. As a result, many existing household water service lines still contain lead. Lead service lines are more commonly found in older cities and houses built before 1986. Lead can leak from pipes via corrosion into the water supply. While most contaminants are detected and treated at a water treatment facility, this does not protect against contamination that enters the water supply while it travels to its final destination. Permanent solutions to reduce lead exposure include replacing lead service lines and can cost from $1,200 to $12,300 for the entire line according to the Environmental Protection Agency (EPA). A less permanent solution is to treat water to be less corrosive. The EPA has also shown that, when properly installed and used, filters designed for lead removal are effective at removing lead. In the 2022 Missouri Legislative Session, three bills have been introduced (HB 2532, HB 2610, SB 1075) that aim to lower the levels of lead in school drinking water sources to one part per billion.