Evaluation of Changes in Lead Levels in Drinking Water Due to Replacement of Water Mains: A Comprehensive Study in Chicago, Illinois.

Disturbances to water treatment and distribution systems using lead service lines have been reported to increase water lead levels. This study evaluates effects from one type of physical disturbance, namely, water mains replacement. Lead concentrations at 542 homes in Chicago, Illinois were measured using partial profile sampling (1, 4, 6 and 5 min 1-L samples) after 6-h stagnation, both before and after mains replacement; a subset had monthly follow-up sampling for an additional 12 months.