Congressman Mike Quigley and Illinois Attorney General Lisa Madigan joined them Sunday for a boat tour of the river.
The Environmental Protection Agency recently ordered state officials to adopt stricter water quality standards.
The EPA wants to make stretches of the river and connecting waterways clean enough for recreational use.
Currently, billions of gallons of partially treated sewage are pumped into the river each year.
"I'm particularly worried that this is one of the only cities left in the industrialized world that does not disinfect its sewage water," said Kirk.
"This is a great city. This river can be a great part of the future of this city," said Durbin. "Our generation needs to step in and clean up the Chicago River."
Quigley said it is time to quit treating a great natural treasure like a toilet.
Some people within the Metropolitan Water Reclamation District have called it a waste of money to make the river safe for swimming.