Studies have been made of the uptake of lead into drinking water and the association of that with the blood lead of persons resident in houses supplied with such water. Significant regressions were found between water lead and blood lead concentrations. Very high concentrations were found in houses with lead plumbing. There were in addition increased lead concentrations found in houses using copper piping joined with lead soldered joints. These studies have suggested that some health hazards might be expected to be associated with the increased environmental uptake of lead in these situations.