New laws have been passed because lead is unhealthy for humans, especially children. Small amounts of lead that would not harm an adult can disrupt a child's normal growth and mental development.
Few waters contain naturally high sources of lead.
Federal and State laws require the Milwaukee Water Works to treat the water to reduce lead. The lead is continuously leached into the water by plumbing materials containing lead, such as lead pipes, lead solder on copper pipes, or brass fixtures. The rate can vary greatly with the variations in natural water quality and the age of the plumbing system. When the water stands motionless for extended periods of time, such as overnight, lead concentrations in the water can sometimes increase greatly. There is no detectable lead in water leaving the Milwaukee treatment plants.