But the city bears some responsibility for lead showing up in water. Chicago has been replacing public water mains, borrowing $312 million for the program since Emanuel took office in 2011. Main replacement can shake loose the protective coating within the lead service lines and cause lead to leach into water as it reaches residences. "City actions have increased the levels of lead in the water," Cook County Circuit Judge Raymond Mitchell wrote as part of his ruling this month in a lawsuit seeking the removal of lead service lines in Chicago. Mitchell dismissed the suit, citing case law that limits Illinois residents who seek damages when government actions cause harm. But he offered a blunt verbal judgment: "The city nevertheless pursues its projects and insists that the water is safe to drink."