Chicago Mayor Rahm Emanuel launched a $4.1 billion initiative to replace his city’s dilapidated water infrastructure last month, spinning it as a plan to create 18,000 jobs over the next decade. The rub is that by 2015, most Chicagoans would pay more than double their current water usage fees. “The work here, in my view, is essential for Chicago’s economic future,” Emanuelsaid at a construction site where crews replaced piping dating to 1886.