Why is lead in some homes?

Lead is a highly toxic metal that was used for many years in products found in and around our homes. In general, the older a home, the more likely it has lead-based paint.
The most common sources of household lead are:
Paint- The federal government banned lead-based paint from housing in 1978, but homes built before this time may have used lead paint.
Dust- Household dust can be contaminated with lead from paint, as can the soil around a house whose exterior was painted with lead paint.
Drinking water- Your home might have plumbing with lead or lead solder used to join the pipes.
Can lead cause health problems?

If not detected early, children with high levels of lead in their bodies can suffer from damage to the brain and nervous system, behavior and learning problems, slowed growth, hearing problems and headaches. 

Lead is also harmful to adults. Adults can suffer from difficulties during pregnancy, high blood pressure, digestive problems, nerve disorders, memory and concentration problems, and muscle and joint pain.