The conventional wisdom of lead‐scale solubility has been built over the years by geochemical solubility models, experimental studies, and field sampling using multiple protocols. Rarely have the mineral phases from scales formed in real‐world drinking water lead service lines (LSLs) been compared with theoretical predictions. In this study, model predictions are compared with LSL scales from 22 drinking water distribution systems. The results show that only 9 of the 22 systems had LSL scales that followed model predictions. The remaining systems had unpredictable scales, some with unknown lead release characteristics, demonstrating that predicting scale formation and lead release solely by models cannot be relied on in all cases to protect human health. Therefore, for many systems with LSLs, pilot studies with existing LSL scales will be necessary to evaluate and optimize corrosion control, and correspondingly, appropriate residential water sampling will be needed to demonstrate consistent and optimal system corrosion control.

Following a pH reduction in their drinking water over a span of more than 20 years, the City of Newark, New Jersey, has struggled with elevated lead (Pb) release from Pb service lines and domestic plumbing in the zone fed by the Pequannock Water Treatment Plant. In response, Newark initiated orthophosphate addition and provided faucet-mounted point-of-use (POU) filters and pitcher filters certified for Pb and particulate reduction under NSF/ANSI Standards 53 and 42 to residential homes in that zone. Water chemistry analysis and size fractionation sampling were

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With lead service lines (LSLs) remaining for decades to come, scale analyses are critical to helping limit lead exposure from drinking water. This laboratory has used an integrated suite of analytical techniques to characterize the elemental composition, mineral identification, and physical features of scales, helping the water industry to evaluate, predict, and reduce lead corrosion. The methods used in this laboratory to prepare and analyze the LSL scale, and guidance to achieving reliable and meaningful results, are described. Primary methods include the following: optical microscopy, powder X‐ray diffraction, inductively coupled plasma spectroscopy, X‐ray fluorescence, scanning electron microscopy with energy dispersive spectroscopy, combustion and coulometric analyses of C and S, and X‐ray absorption spectroscopy. Examples of associated pitfalls and ways to avoid them are provided, including pipe excavation/transport, sample preparation, analysis, and data interpretation. Illustrative examples are presented of practical scale analysis questions that could be answered by combinations of pipe scale analyses.