Homes built prior to 1980 are likely to contain lead-based paint even though the actual ban was in place in 1978. According to the Environmental Protection Agency (EPA):

Lead can also be present in drinking water, soil and dust. Lead is very toxic to children, if you have kids, you may wish to have them tested for elevated blood lead levels if you are experiencing health problems related to lead poisoning. Knowing whether your property contains lead paint is particularly important if you plan on remodeling or even sanding. Home sellers, lessors, buyers, or renters may also be interested in lead testing.