Mayor Richard M. Daley mocked federal officials when they asked that the Chicago River be made clean enough to swim in, but mayor-elect Rahm Emanuel’s administration is supporting a federal demand to do just that.

In a statement to WBEZ, a spokesperson for Rahm Emanuel said Chicago’s mayor-elect supports the more stringent water quality rules that the federal Environmental Protection Agency is pushing.

“By making its waters safe and clean, we can restore the River as a center for recreation and unlock its full potential to enhance Chicagoans’ quality of life,” the statement reads.

Emanuel’s stance is markedly different from that of current Mayor Richard M. Daley, who told federal water regulators to “go swim in the Potomac” when the EPA previously encouraged a clean-up of the Chicago River last summer.

Emanuel’s statement is in response to the EPA’s demand that local officials make the Chicago River clean enough to swim in - and the feds are threatening to step in if they don’t.

In a letter sent to the state on Wednesday, the EPA said Illinois is long overdue to clean up several Chicago-area waterways, including the River and the Cal-Sag Canal. About 70 percent of the water in those bodies is treated sewage discharge, but local water officials are not currently required to disinfect the discharge in order to kill off microscopic bacteria. The EPA’s demand would change that.

Some members of the Metropolitan Water Reclamation District of Greater Chicago, which has authority over the waterways, have dismissed those plans as too expensive. They’ve also maintain that those waterways are primarily commercial and unsafe for swimming.

But gone are the days when no Chicagoan would deign to take a dip in their hometown river, said Susan hedman, Regional Administrator for the federal EPA in the Midwest. More and more, people are using the river for recreation, Hedman said.

“It’s very clear that this is not primarily a commercial waterway anymore,” Hedman said. “All of the investments that have been made in the River Walk, in boat ramps, in other access points … have brought people to the river, and people are now actively recreating on the river.”

Plans to make the Chicago-area waterways swimmer-friendly have been bogged down since 2007, said Marcia Willhite, who heads up the Bureau of Water for the Illinois EPA. That’s when her agency proposed the swimmer-friendly rule changes to the Illinois Pollution Control Board, which conducts hearings and must sign-off on the letter.

“It’s just been an unprecedented length of [hearings], and we are not done yet,” Willhite said.

In its letter to the state, the federal EPA said it expects Illinois to adopt the new water rules “expeditiously,” though a spokeswoman would not give a specific timeline.

If the state does not act, the federal government can fast-track the rulemaking process, Hedman said.