Evaluation of flushing and corrosion control to lower lead levels at the taps in households with lead service lines

“Lead service lines (LSLs) were commonly installed in buildings in many countries including Canada until 1975 [1]. Although their use was banned by then, many of these buildings still have these pipes in place. While there is agreement that all lead service lines should be replaced [2], lead service line replacement process is slow and challenging due to the associated costs. Moreover, water conservation strategies are increasing in response to regulatory requirements addressing the need to lower environmental footprint and respond to water shortage [3]. Implementing certain strategies for reducing water consumption can exacerbate the problem of lead leaching, as it increases stagnation of water in the buildings [4]. While fully replacing all LSLs can be a time-consuming process and with water conservation programs in place, corrosion control or other mitigation strategies such as flushing are required to reduce the potential risk of exposure to elevated lead levels.
Guidelines and standards for lead in drinking have been improved over time. A new standard of 5 μg/L as the maximum acceptable concentration for total lead in drinking water is now proposed by health Canada [5] and to be implemented in European countries by 2036 [6]. Numerical approaches can be useful tools for estimating the typical exposure level at the household level, which the results can then be used as the basis to assess compliance and implement necessary remedial measures. Lately, several studies modelled variation of dissolved lead concentrations at the tap using EPANET [7-10]. This study focus on simulating the impact of different water demand scenarios on variation of lead levels at the kitchen tap of a simple household drinking water system using hydraulic and water quality numerical tools based on calibrated lead dissolution model parameters. The impact of corrosion control as well as different flushing strategies are then evaluated.”

(Citation: Hatam, F., Blokker, E.J.M., Provost, M. – Evaluation of flushing and corrosion control to lower lead levels at the taps in households with lead service lines – 19th International Computing & Control for the Water Industry Conference, 4-7 September 2023)