As recently as September, mayoral aides and water department officials continued to insist that it is up to individual homeowners to protect themselves from mostly invisible particles leaching out of lead pipes the city required by law for decades. On Wednesday, Emanuel himself declared Chicago’s drinking water is safe while opposing plans introduced in the City Council to finance the replacement of lead service lines. He accused the measure’s authors of treating homeowners “as an ATM machine” by proposing to pay for the project with a 1 percent tax on sales of Chicago homes worth more than $750,000.