Infrastructure upgrades and lead exposure : do cities face trade-offs when replacing water mains?

Concerns about drinking water contamination through lead service lines, which connect street water mains to homes in many cities in the United States, might hinder resource-constrained municipalities from performing important infrastructure upgrades. Construction on water mains might disturb the service lines and increase lead levels in drinking water. We estimate the effects of water main maintenance on drinking water and children's blood levels by exploiting unique geocoded data and over 2200 water main replacements in Chicago, a city with almost 400,000 known lead service lines. By comparing water and blood samples in homes at different distances from replaced mains before and after replacement, we find no evidence that water main replacement affects water or children's lead levels