Estimating Health Damages from Lead Pipe Disturbances: Evidence from Chicago

Although lead poisoning has increasingly been identified as an important public health problem, many children are exposed to lead through drinking water leaching from old lead pipes. Over time, sediments accumulate in the service lines that connect homes to water mains, preventing lead from leaching into water. Exposure could happen when utility companies upgrade or replace their water mains, which may shake the service lines, removing the protective coating. Yet, little is known about the impact of routine pipe maintenance on child blood lead levels (BLLs). We exploit a large-scale water main replacement program in Chicago and a unique combination of geocoded data sources to causally estimate the effects of pipe maintenance on children’s blood levels and drinking water quality. By comparing tests in homes in the same neighborhood but at different distances from over 2,300 construction projects before and after construction, our identification strategy relies on the exogeneity of test timing and main replacement in their neighborhood. We find no evidence that main construction affects children's health by increasing BLLs or the lead content of drinking water.