This study found evidence isolating the source of lead contamination to various specific components in the plumbing system such as brass valves and soldered brass elbows. Mechanical operation of a valve was found to cause a large increase in lead concentration, possibly due to hydrodynamic scouring or to mechanical wear. Finally, it was found that sources of lead near, but not in the line with the sampled flow can contribute lead contamination to that flow. The study also demonstrates how spatial sampling can identify sources of lead contamination. This could potentially reduce the cost of modifying plumbing systems for removal of those sources, although the added analytical cost must be considered. However, accumulation of a number of spatially distributed samples could enable a utility to predict which fittings are most likely causing particular problems, leading to more cost-effective solutions.