AWWA WQTC69502

This paper summarizes results from a recently completed AwwaRF study titled, "Contribution of Service Line and Plumbing Fixtures to Lead and Copper Rule Compliance Issues." Total and dissolved lead levels were measured in consecutive sequential standing tap samples at residential sites in six utility locations. Results provide an indication of the relative contribution of various lead sources (faucet, premise, lead service) to lead levels measured at the tap, both in terms of total mass of lead measured at the tap, and LCR compliance. Results indicate that the presence of a lead service at an individual site may elevate the contribution of individual sources by providing an additional source of lead, either by introducing lead derived from the service at the start of the stagnation period, or by "seeding" the premise system with lead. This lead can then be incorporated into the scales built up on the surfaces of the premise piping (including the faucet), from which it can be released over time depending on physical and chemical conditions. Lead can then be taken up into the water during stagnation and measured in standing samples collected at the tap, or picked up during flowing conditions. These results provide the water industry with additional information on the impact that material sources of lead may have on lead levels at the tap and how this might impact LCR compliance. Results also address the broader long-term goals of moving the industry towards a new "lead free" future and providing information that can be directly applied to future regulatory reviews of the LCR. Includes 12 references, tables, figures.