The dynamics of lead in drinking water in U.S. workplaces and schools.

A statistical analysis of water samples from over 12,000 school and workplace water coolers, bubblers, chillers, faucets, and ice makers determined that there is a substantial risk of excessive lead concentrations in first-draw water from sources of all types. Of all sources tested, 17.2% had lead concentrations in excess of 15 ppb. A comparison of lead concentrations by brand of water cooler was made for all manufacturers for which at least 50 samples were available. The percentage of water sources with first-draw lead concentrations above 15 ppb was reduced by 58%-84% by flushing the source prior to use. Special attention was given to determining the relationships between lead levels and factors such as water pH, water cooler age, and line purging. While each of these variables was found to be statistically significant, the overwhelming indication of this research is that testing individual water sources is apparently the only reliable way to determine whether a lead contamination problem exists.